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Surface Water Management Plan Pilbara Regional Waste Management Facility Shire of Ashburton

TW18004 - Surface Water Management Plan.1c October 2018 |

Assets | Engineering | Environment | Noise | Spatial | Waste

Surface Water Management Plan

Pilbara Regional Waste Management Facility

Prepared for Shire of Ashburton

October 2018

Project Number: TW18004


TW18004 - Surface Water Management Plan.1c October 2018 | Page 1

DOCUMENT CONTROL

Version Description Date Author Reviewer

0a Internal Review 28/06/18 LW+CP LM

1a Draft Released to Pells Sullivan Meynink for

Review 18/07/18 CP LM

1b Released to Client for Review 04/09/18 CP LM

1c Final Report 15/10/18 CP LM

Approval for Release

Name Position File Reference

Ronan Cullen Director and Waste

Management Section Leader TW18004 - Surface Water Management Plan.1c

Signature

Copyright of this document or any part of this document remains with Talis Consultants Pty Ltd and cannot be used,

transferred or reproduced in any manner or form without prior written consent from Talis Consultants Pty Ltd.



Table of Contents 1 Introduction ......................................................................................................................... 5

1.1 Background ............................................................................................................................. 5

1.2 Scope of Works ....................................................................................................................... 5

2 Site Description .................................................................................................................... 6

2.1 Site Information ...................................................................................................................... 6

2.2 Environmental Attributes ....................................................................................................... 6

2.2.1 Topography ............................................................................................................... 6

2.2.2 Geology ..................................................................................................................... 6

2.2.3 Surface Water ........................................................................................................... 7

3 Local Climate Data ................................................................................................................ 8

3.1 Temperature ........................................................................................................................... 8

3.2 Rainfall .................................................................................................................................... 8

3.2.1 Short Duration Design Rainfall .................................................................................. 9

3.3 Pan Evaporation .................................................................................................................... 10

3.4 Regional Flood Trends ........................................................................................................... 11

4 Surface Water Management Strategy .................................................................................. 12

4.1 Key Infrastructure ................................................................................................................. 12

4.1.1 Perimeter Drains ..................................................................................................... 12

4.2 Surface Water Modelling ...................................................................................................... 12

4.2.1 Catchment Areas ..................................................................................................... 12

4.2.2 Swale System ........................................................................................................... 14

4.2.3 RORB........................................................................................................................ 16

4.3 Surface Water Infrastructure Design .................................................................................... 17

4.3.1 Perimeter Drains ..................................................................................................... 17

4.3.2 Surface Water Ponds ............................................................................................... 19



4.3.3 Other Associated Infrastructure.............................................................................. 20

4.3.4 Summary ................................................................................................................. 22

4.4 Operational Management and Monitoring Strategy ............................................................ 23

5 Local Flood Risk Assessment ............................................................................................... 24

5.1 Levee Embankment Design ................................................................................................... 24

5.2 Design Review ....................................................................................................................... 25

Figures ....................................................................................................................................... 26

Tables Table 3-1: Average Maximum and Minimum Temperatures (°C) at Onslow Airport (1940-2017)

Table 3-2: Rainfall Overview at Onslow Airport (1940-2017)

Table 3-3: Pan Evaporation Data for the Onslow Area in Millimetres (mm)

Table 4-1: Summary of Catchment Areas

Table 4-2: Key Design Considerations for Swale System

Table 4-3: Key Design Characteristics of the Swale System

Table 4-4: Modelling Results of the Swale System

Table 4-5: RORB Modelling Results for Pond Storage Requirements

Table 4-6: Design Characteristics of Surface Water Pond System

Table 4-7: Rock Armouring Details for Swale System

Table 5-1: Key Design Characteristics of the Levee Embankment

Table 5-2: Minimum Rock Armouring Details for Levee Embankment

Diagrams Diagram 3-1: Onslow Airport Rainfall from 1940 -2017

Diagram 3-2: Summary of IFD Design Curves



Diagram 4-1: Catchment Overview

Diagram 4-2: Swale Geometry

Figures Figure 1: Locality Plan

Figure 2: Topography

Figure 3: Hydrology

Figure 4: Catchment Areas

Appendices : Drawings

: RORB Modelling Results

: Surface Water Drainage and Pond System Design Calculations

: Culvert and Rock Armouring Design Calculations

No tabl e of content s entrie s found.



1 Introduction

Talis Consultants Pty Ltd (Talis) was commissioned by the Shire of Ashburton (the Shire) to prepare

the approval documentation for the Pilbara Regional Waste Management Facility (the Site). As part of

the supporting documentation, a Surface Water Management Plan (SWMP) has been developed,

summarising the assessments and strategy for managing surface water during the development,

operation and closure of the Site.

1.1 Background

The Shire of Ashburton is progressing with the development of a new regional waste management

facility located at Lot 150 Onslow Road, Talandji, Western Australia. With the rapid increase in

industrial development and its associated growth within the Shire and Pilbara Region, there will be a

significant increase in the volume of waste generated. Therefore, the Shire identified the need for the

establishment of a new facility that can meet the waste management needs of Onslow and the wider

Pilbara region.

The project, referred to as the Pilbara Regional Waste Management Facility (PRWMF), will provide a

range of waste management services including sustainable initiatives such as reuse, recycling and

recovery as well as treatment and disposal. The proposed Class IV facility and its associated

infrastructure will be designed and constructed to Environmental Protection Authority (EPA) Victoria’s

Best Practice Environmental Management Guidelines for the Siting, Design, Operation and

Rehabilitation of Landfills (August 2015) (Best Practice Landfill Standards). It will consist of a double

composite lined landfill cells with leachate collection that will accept municipal solid waste and

commercial waste, as well as contaminated soil and sludge (including encapsulated wastes).

1.2 Scope of Works

The SWMP contains the following scope of works:

Site description;

Local climate data;

Surface Water Management Strategy;

o Surface water management requirements;

o Surface water generation modelling;

o Surface water infrastructure requirements;

o Operational management and monitoring strategy; and

Local flood risk assessment.



2 Site Description

2.1 Site Information

The Site is located approximately 36km south of Onslow within Lot 150 Onslow Road, Talandji, which

occupies an area of 434 hectares (ha). The proposed Site footprint occupies a total of approximately

70ha and is accessible from Onslow Road, which is a main road and primary distributor. The Site is

located behind an approximately 3km long sand ridge and, therefore, most of the PRWMF will not be

visible from Onslow Road.

2.2 Environmental Attributes

The following sections outline the key existing environmental attributes of the Site, including

topography, geology and surface water, which affect the development of the surface water

management system.

2.2.1 Topography

The Site is relatively flat, with a gentle slope across the sand plain towards the north-west and the

Indian Ocean. The Site topography ranges from 17 to 13 metres (m) Australian Height Datum (AHD)

on the lower sand plain to 40mAHD along the crest of the sand ridge. A number of surface depressions

of various sizes are distributed across the sand ridge. The topography of the Site is provided in Figure

2.

2.2.2 Geology

In 2017, Talis was commissioned by the Shire to undertake a geotechnical investigation of the Site. As

part of the works, a total of 112 trial pits (TP01-TP112) were excavated across the Site to assess the

shallow subsurface, and to allow the collection of bulk soil samples for laboratory testing. The trial

excavations described the underlying soil horizon to primarily be a SAND, with its structure described

as fine to medium grained, rounded to sub rounded, dry and loose with occasional roots. It was also

described as a SILTY SAND/SANDY SILT of low plasticity. This horizon is colloquially known as ‘Pindan’.

This horizon was encountered to a maximum depth of between 0.5m and 5m below ground level.

The conditions were recorded to be generally homogenous across the Site. Therefore, the following

generalised profile has been determined for the Site:

SAND – loose, fine to medium grained (Pindan) generally corresponding to the sand dune

ridge;

Sandy clayey SILT/Silty clayey SAND – loose to dense, fine to medium grained, rounded to sub-

rounded, red brown and dry (Pindan); underlain by

Cemented GRAVEL/SILCRETE – cemented gravels in silty sand/sandy silt matrix – hard, red

brown and white, becoming brown with depth, and dry; underlain by

SANDSTONE interfingered with cemented gravel – medium grained, occasional clasts,

siliceous veins and vugs, dry, red to yellow.



2.2.3 Surface Water

There are no surface water bodies located within the Site. The nearest surface water body identified

in NationalMap is a salt lake located approximately 2.5km west from the boundary of the Site. The

Site is located in between two major ephemeral watercourses. The Ashburton River is located

approximately 20km south-west of the Site and the Cane River is located approximately 21km to the

north-east. The Site is located within the Ashburton River Catchment Area (Figure 4). These major

rivers discharge over the coastal flats towards the Indian Ocean. According to the Department of

Water’s ‘Pilbara Regional Water Plan 2010-2030 Supporting Detail’ (May 2010), these rivers are highly

seasonal and variable and flow following rainfall and cyclonic activities. The hydrology and

hydrographic catchments surrounding the Site are shown in Figure 3 and 4 respectively.



3 Local Climate Data

The local and regional climate data sources utilised in designing the surface water management

systems at the Site, include the following:

Pan evaporation;

Intensity Frequency Duration

o Design rainfall depth;

o Design rainfall intensity;

Areal-reduction factors;

Storm losses; and

Areal temporal patterns.

Historic weather data was sourced from the Bureau of Meteorology (BOM) website utilising the

Onslow Airport weather station data (Station ID: 005017): http://www.bom.gov.au/climate/data/.

The station is approximately 4 kilometres (km) from the coast and approximately 30km from the Site.

3.1 Temperature

The climate of the Onslow area is considered to be a grassland climate and arid with a hot, humid

summer zone. Table 3-1 shows the mean minimum and maximum temperature at the Onslow Airport

from 1940 to 2017.

Table 3-1: Average Maximum and Minimum Temperatures (°C) at Onslow Airport (1940-2017)

Aspect Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual

Minimum 24.4 25.0 24.2 21.4 17.4 14.3 13.0 13.6 15.4 17.9 20.1 22.4 19.1

Maximum 36.4 36.3 36.1 33.9 29.3 26.0 25.4 27.3 30.1 32.9 34.4 35.9 32.0

As shown above, the lowest minimum mean temperature for Onslow is 13.0°C during the winter

months and highest maximum mean temperature is 36.4°C during the summer months.

3.2 Rainfall

Being an arid zone, the wet season for the Pilbara region occurs from December to April each year.

Table 3-2 and Diagram 3-1 presents the summary of rainfall records collected from the Onslow Airport

from 1940 to 2017.

Table 3-2: Rainfall Overview at Onslow Airport (1940-2017)

Aspect Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual

Average 38.6 61.0 72.0 11.4 48.6 45.5 20.3 8.6 1.4 0.8 2.8 3.4 314.4

90th

Percentile 112.4 179.2 248.6 28.9 111.8 111.6 51.3 30.0 2.2 1.6 4.7 6.7 540.5

Highest 275.6 358.6 374.9 163.4 236.7 230.8 115.4 81.8 24.7 15.0 60.2 54.0 1,085.1

http://www.bom.gov.au/climate/data/



Diagram 3-1: Onslow Airport Rainfall from 1940 -2017

The mean annual rainfall for Onslow is reported as 314.4 millimetres (mm). Regionally, the Ashburton

River Catchment Area’s mean annual rainfall varies from 230mm to 400mm. Mean annual rainfall

trends downwards heading east from the coast and south from the Hamersley Range (approximately

150km east of the Site). Larger rainfall events are typically associated with tropical cyclones and large

low pressure systems that most frequently affect the region between January and March.

3.2.1 Short Duration Design Rainfall

Rainfall Intensity Frequency Duration (IFD) data for Onslow was obtained using the BOM

Computerised Design IFD Rainfall System (CDIRS) and the Australian Rainfall and Runoff 2016 database

(ARR2016). CDIRS produces a complete set of IFD curves and associated weather data based on user-

defined coordinates.

Table 3-1 summarises the Annual Exceedance Probability (AEP) of storms with 1 to 72 hour (hr)

durations. Rare historic weather events with recurrence intervals of up to 1000 years have also been

included for 24, 48 and 72hr durations. AEPs are required to estimate design flood discharges for a

range of events can be found in Diagram 3-2.

Table 3-1: Summary of Annual Exceedance Probabilities for Onslow Airport (ARR2016)

Storm

Duration

1 in 10 1 in 20 1 in 50 1 in 100 1 in 200 1 in 500 1 in 1000

10% 5% 2% 1% 0.5% 0.2% 0.1%

Rainfall Depth (mm)

1 hour 53.5 63.6 77.4 88.3 - - -

2 hour 70 83.8 103 118 - - -

3 hour 82.3 99.2 123 142 - - -

6 hour 110 134 169 197 - - -

12 hour 146 182 231 272 - - -

24 hour 188 235 301 355 426 515 589

0

50

100

150

200

250

300

350

400

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Mill

ime

tre

s

Average

90th Percentile

Highest



Storm

Duration

1 in 10 1 in 20 1 in 50 1 in 100 1 in 200 1 in 500 1 in 1000

10% 5% 2% 1% 0.5% 0.2% 0.1%

Rainfall Depth (mm)

48 hour 222 278 355 419 493 592 675

72 hour 234 291 370 436 509 609 692

Diagram 3-2: Summary of IFD Design Curves

According to Best Practice Landfill Standards, the storage ponds and other components of the

management system should be designed to contain and control surface water runoff from a 1-in-20

year storm event, at a minimum, for putrescible landfills. However, storm events up to 1-in-100 year

recurrence intervals should also be considered to ensure that they do not result in any catastrophic

failures such as flooding of the landfill or failure of dams or leachate storage ponds. Therefore, 1-in-

100 year, 72hr storm events have been considered for the design of the surface water management

infrastructure at the Site.

3.3 Pan Evaporation

The Onslow Airport weather station does not record mean daily evaporation. Therefore, monthly

evaporation rates were interpolated from BOM’s 1975-2005 Average Pan Evaporation Map

(http://www.bom.gov.au/jsp/ncc/climate_averages/evaporation/index.jsp?#maps).

The approximate average daily pan evaporation rates were calculated from the monthly rates. The

pan evaporation data for the Onslow has been provided in Table 3-3.

http://www.bom.gov.au/jsp/ncc/climate_averages/evaporation/index.jsp?#maps



Table 3-3: Pan Evaporation Data for the Onslow Area in Millimetres (mm)

Description Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual

Monthly 350 300 300 300 175 125 125 175 250 300 350 400 3,150

Daily Average 11.3 10.7 9.7 10.0 5.6 4.2 4.0 5.6 8.3 9.7 11.7 12.9 8.6

The daily average pan evaporation ranges from 4.2mm to 12.9mm and monthly from 125mm to

400mm. The total annual pan evaporation for Onslow is reported as 3,150mm.

3.4 Regional Flood Trends

The Site is located on the Onslow Coastal Plain between two major river systems namely the

Ashburton River and the Cane River. Due to the nature of the regional topography and the proximity

to flowing water systems, the area around the Site could be subject to flooding either by direct rainfall

or by regional overland flow. During the site selection works, a regional flood study was undertaken

by Pells Sullivan Meynink (PSM) in August 2017.

The regional flood study included regional and local hydrologic and hydraulic analysis which covered:

Rainfall runoff modelling of the Ashburton River catchment;

Flood frequency analysis of the Ashburton and Cane river stream flow gauges;

Regional methods of peak flow estimation;

Hydraulic modelling of the Onslow Coastal Plain in the region downstream of the Ashburton

and Cane River stream flow gauges;

High spatial resolution hydraulic modelling of the area around the Site, supported by a

topographic survey; and

Sensitivity testing of selected model parameters.

The assessment concluded that regionally direct rainfall and local runoff is responsible for the largest

flows impacting the Site. It was also established that flows from the Ashburton River were capable of

reaching the Site but not from the Cane River. The south-western half of the Site was affected by

significant upstream flows. However, a lack of defined surface channels resulted in shallow, low

velocity (typically less than 0.5m/s) flow even during significant weather events.

Based on the conclusions from the flood study, it was recommended that surface water management

infrastructure include drainage and flood protection designs.

As a result of the study, along with some other key engineering design considerations, the

development footprint for the landfill at the Site was re-located adjacent to the pindan sand ridge line,

which experienced minimal to no risk of flooding.



4 Surface Water Management Strategy

The surface water management strategy for the Site will closely align with Best Practice Landfill

Standards, with the surface water management infrastructure designed to manage and control rainfall

runoff from 1-in-100 year 72hr storm events. The infrastructure for the surface water management

system will include attenuation/infiltration ponds, a levee embankment and perimeter drains around

the Site.

The following sections detail the key infrastructure components and their design to ensure that

surface water is appropriately collected, stored and/or diverted based on the regional weather

records.

4.1 Key Infrastructure

4.1.1 Perimeter Drains

Perimeter drains in the form of trapezoidal open channel swales will be utilised to effectively transport

runoff within the Site to collection points for attenuation, infiltration or diversion off-site. The swale

system is critical to minimise the generation of leachate, increase control over erosion, and mitigate

the risk of localised flooding. The ultimate design of the system incorporated the restoration profile

of the landfill after its closure to ensure that the system can appropriately manage surface water

during the closure and aftercare period of the landfill.

4.2 Surface Water Modelling

To determine the appropriate design for the proposed surface water management infrastructure,

modelling was undertaken utilising a Microsoft Excel surface water pond and swale sizing algorithm

initially and further defined through Runoff Routing software (RORB). RORB is a general runoff and

streamflow routing program used to calculate flood hydrographs from rainfall and other inputs for

urban and rural applications. RORB subtracts rainfall losses due to ground seepage to determine the

route of excess surface water through the model.

4.2.1 Catchment Areas

To assist modelling, the Site was split into sub-catchment areas, with the Site divided into four sub-

catchments based on topographical data, the design of the landfill and other supporting

infrastructure. The catchment area are illustrated in Diagram 4-1 and are labelled as the following:

1: Northern Catchment;

2: North-eastern Catchment;

3: Southern Catchment; and

4: Landfill Catchment.



Diagram 4-1: Catchment Overview

The Southern Catchment area excluded the leachate and surface water ponds to reflect post-

development of infrastructure. These areas are depicted in white in Diagram 4-1, and account for a

minor reduction in potential runoff from the catchment area. The Landfill Catchment assumes the full

restored landfill profile after operations are complete. Only the surface water from the Landfill

Catchment will contribute to the surface water attenuation and infiltration pond system. The surface

water from the three remaining catchments will be diverted directly from the Site through the use of

the perimeter drains.

Table 4-1: Summary of Catchment Areas

Catchment Catchment Area (ha)

1: Northern 5.937

2: North-eastern 13.262

3: Southern 35.920

4: Landfill 19.020

Total 74.139

The catchment areas identified in Table 4-1 are utilised to calculate the capacity of the surface water

ponds and the swale system across the Site.

4.2.1.1 Runoff Coefficient

The site geology (as discussed in Section 2.2.2) consists of Pindan sand soil horizons.

While a runoff coefficient value of 0.1 would be acceptable for vegetated sands of a similar grading,

Pindan sand is highly variable and can display self-cementation properties which can result in an

increased runoff despite a vegetated and irregular terrain. Therefore, for the purpose of the

calculations the runoff coefficient for the each of the catchments is assumed to be 0.40.



4.2.1.2 Kerby’s Roughness Factor

With regards to Kerby’s roughness factor, the description of the area is considered to be smooth bare

soil, therefore for the modelling works a roughness factor of 0.10, has been utilised. This is a

conservative value that simulates a worst-case scenario. It essentially means that as the surface water

travels across the catchment area to the swale its velocity is not slowed down by the roughness of the

surface.

4.2.2 Swale System

The Microsoft Excel spreadsheet algorithm uses the Kerby-Kirpich Method to determine the flow rate

of the surface water through the swale system during a specified rainfall event. In order to use this

method, the movement of the surface water through the swale system has been conceptualised with

the key components of the swale system outlined in the following sub-sections.

4.2.2.1 Kerby-Kirpich Method

The swale system was designed using a Microsoft Excel algorithm modelled after the Kerby-Kirpich

method to estimate the watershed time of concentration (tc) for a rainfall event. The method requires

adding the overland flow time (Kerby, tov) to the channel flow time (Kirpich, tch) in order to obtain the

time of concentration. The following equations were utilised to determine the time of concentration:

𝑡𝑐 = 𝑡𝑜𝑣 + 𝑡𝑐ℎ Eq. 1

where

𝑡𝑜𝑣 = 1.44 × (𝐿 × 𝑁)0.467 × 𝑆−0.235 L = Length of overland flow N = Kerby’s roughness coefficient, 0.10 S = Slope gradient of the overland flow

Eq. 2

where

𝑡𝑐ℎ = 0.0195 × 𝐿0.770 × 𝑆−0.385 L = Length of swale flow S = Slope gradient of the swale flow

Eq. 3

Once the time of concentration has been determined, then the theoretical peak flow rate through

each swale can be calculated and compared to the maximum allowable flow rate through the swale

as determined by the design geometry of the swale. If the maximum allowable flow rate is greater

than the theoretical peak flow rate, then the design of swale has passed. The following equations

were utilised to perform this design check:

where

𝑄𝑡 = 𝐶 × 𝐼 × 𝐴 𝑄𝑡 = Theoretical peak flow rate, m3/hr C = Runoff coefficient, 0.40 I = Rainfall intensity at time of concentration, m/hr A = Catchment surface area, m2

Eq. 4



where

𝑉 = 1 𝑛⁄ × 𝑅ℎ2/3

× 𝑆𝑠1/2

V = Velocity of surface water through the swale n = Manning’s coefficient 𝑅ℎ = Hydraulic radius 𝑆𝑠 = Slope of swale

Eq. 5

where

𝑄𝑎 = 𝑉 × 𝐴𝑠 𝑄𝑎 = Maximum allowable flow rate, m3/hr V = Velocity of surface water through the swale, m/hr 𝐴𝑠 = Cross-sectional area of the swale, m2

Eq. 6

4.2.2.2 Surface Water Movements

A series of catch drains/swales for clean and potentially ‘dirty’ water systems will be constructed

around the facility to enable the effective management of surface water. The surface water

movement/interaction between the swales and Site infrastructure/roads is discussed as follows.

A swale will be constructed around the south-eastern boundary of the landfill development footprint.

The swale will direct potentially ‘dirty’ water into the surface water attenuation pond and

infiltration/evaporation pond system. A Site access road will cross over the discharge channel to the

surface water ponds and will therefore require a culvert to be constructed.

The North-eastern Catchment swale will direct clean flow south eastwards towards the Southern

Catchment swale. To enable discharge into the Southern Catchment swale, a culvert will be required

under the main Site access road and the southern bushfire control access road.

The Southern Catchment swale will be constructed along the entire interior perimeter of the levee

embankment, and discharge into the sand plain north-west of the Site. Any overflow from the

Infiltration/Evaporation Pond #2 will also connect into the swale to direct water offsite. The southern

bushfire control access road will cross the offsite discharge swale and will require the installation of a

culvert.

The Northern Catchment swale directs surface water flow north-westerly around the perimeter of the

landfill development footprint then westerly towards the junction with the Southern Catchment

swale. At this point, the surface water will be allowed to flow offsite into the regional sand plain. In

addition, the overflow from Infiltration/Evaporation Pond #1 will connect to the swale. Therefore,

scour protection measures will be required at these two junction points. The Site access road will also

cross over the swale.

4.2.2.3 Manning’s Coefficient

Manning’s coefficient describes the roughness of the swale surface, which is determined by the

material used to construct the swale. The following Manning’s coefficients (n) would be considered

for the swale system:



Unlined earth channel: 0.022;

Bottom and sides lined with riprap: 0.035; and

Bottom and sides lined with HDPE plastic: 0.009.

4.2.2.4 Swale System Design Summary

A summary of the swale system’s design considerations is provided in Table 4-2.

Table 4-2: Key Design Considerations for Swale System

Location Swale Section Manning’s

Coefficient

Average

Gradient Other Key Considerations

Northern

Catchment

A Unlined 0.022 0.009 Two junction points

Two intersection points

with a Site access road

B-

Inclined

Lined-

Riprap 0.035 0.053

C Unlined 0.022 0.002

North-

eastern

Catchment

A Unlined 0.022 0.017 One junction point

One intersection point


B-

Inclined

Lined-

Riprap 0.035 0.039

C Unlined 0.022 0.002

Southern

Catchment A Unlined 0.022 0.001

Three junction points

A significant bend in the

beginning section of

swale



Landfill

Catchment A Lined-HDPE 0.009 0.002

One junction point



Note: If a section of the swale has a slope gradient greater than 0.020, then it is classified as ‘inclined’.

These will be key inputs into the Microsoft Excel algorithm as well as the RORB modelling software.

4.2.3 RORB

4.2.3.1 Data Files

In order to use RORB effectively, region specific modelling files that summarise the weather data for

Onslow was obtained from the Australian Rainfall & Runoff (ARR) Data Hub. The following files were

downloaded and inputted into RORB:

Areal Reduction Factors (ARFs) and losses;

Temporal Patterns; and

BOM IFD data.



For consistency, the coordinates used to obtain these files were the same coordinates for the Onslow

Airport weather station (Station ID: 005017).

4.2.3.2 Initial and Continuing Losses

Instead of using runoff coefficients and Kerby’s roughness factor, the RORB program uses Initial Loss

(IL) and Continuing Loss (CL) to represent the infiltration and excess of surface water during a rainfall

event. IL denotes the infiltration of rainfall during the initial stages of a rainfall event before runoff

begins. CL denotes the continued average infiltration of rainfall per hour during the remaining rainfall

event.

For arid regions, IL range from 10mm to 60mm and CL range from 1mm/hr to 5.5mm/hr. However,

the PSM flood study utilised IL values ranging from 30 to 60 mm, with a fixed CL of 6 mm/hr. For

consistency, the RORB modelling performed to dictate the design of the swale and surface water pond

systems utilised the same values for IL. In order to assess the sensitivity to continuing loss, a CL of

3mm/hr was also modelled.

4.2.3.3 Surface Water Pond Capacity

For further analysis of the surface water pond system requirements, RORB was implemented using

the software’s built-in storage-discharge relationship for a storage pond utilising the following

equation:

where

𝑆 = 𝑘𝑄𝑚 S = Storage volume, m3 k = dimensionless empirical coefficient based on the catchment area Q = Discharge into the storage system, m3/s m = unit-less cross-sectional shape factor, 0.80

Eq. 7

The value of k can be user defined or calculated by the RORB program. For the purposes of this report,

the value of k calculated by the RORB program will be adopted. The results from RORB will be used to

ensure that the surface waste pond system meets the minimum requirements for managing rainfall

from a 1-in-100 year, 72hr duration storm events under various IL and CL conditions.

4.3 Surface Water Infrastructure Design

The following sections describe the modelling results and the finalised design characteristics of the

key infrastructure proposed for the Site’s surface water management strategy.

4.3.1 Perimeter Drains

The perimeter drains will be trapezoidal open channel swales and constructed along the lowest

boundary of each catchment. Diagram 4-2 provides an illustration of the cross-sectional area of the

swale.



Diagram 4-2: Swale Geometry

Based on the geometry depicted in Diagram 4-2, Table 4-3 provides the corresponding values for each

of the different swale designs.

Table 4-3: Key Design Characteristics of the Swale System

Location Design No. [1:S] Side

Slope (V:H)

[b] Bottom

Width (m)

[T] Top

Width (m)

[h] Height

(m)

Northern Catchment 1 1:6 2 14 1

2 1:6 4 16 1

North-eastern

Catchment

1 1:6 2 14 1

2 1:3 2 8 1

Southern Catchment 1 1:6 4 16 1

Landfill Catchment 1 1:6 3 15 1

Note: The swales that are part of the surface water pond system have the same design as the Landfill Catchment swale.

The height of the water was modelled to only reach to an approximate height of 0.5m as a

conservative measure to allow for an approximate 0.5m freeboard.

These swale designs will be required to accommodate flow rates generated in 1-in-100 year, 72hr

duration storm events. The Microsoft Excel algorithm using the Kerby-Kirpich Method and the RORB

program were used to determine whether these are acceptable swale designs.

4.3.1.1 Initial Modelling

Table 4-4 outlines the checks performed using the Microsoft Excel algorithm and the Kerby-Kirpich

Method. The calculations have been provided in Appendix C.

Table 4-4: Modelling Results of the Swale System

Location Swale

Design

Swale

Section

Qt (m3/hr)

[Eq. 4]

V (m/s)

[Eq. 5]

Qa (m3/hr)

[Eq. 6]

Check

Qt < Qa

Northern Catchment

1 A

2,814

1.95 17,552 Pass

1 B 3.01 27,119 Pass

2 C 0.93 11,751 Pass



Location Swale

Design

Swale

Section

Qt (m3/hr)

[Eq. 4]

V (m/s)

[Eq. 5]

Qa (m3/hr)

[Eq. 6]

Check

Qt < Qa

North-eastern

Catchment

1 A

7,180

2.74 24,650 Pass

1 B 2.59 23,321 Pass

2 C 0.99 7,318 Pass

Southern Catchment 1 A 11,681 0.87 12,577 Pass

Landfill Catchment 1 A 8,391 2.17 23,441 Pass

Note: Qt is the theoretical peak flow rate that the swale would need to manage.

V is the maximum velocity of the water through the swale.

Qa is the maximum allowable flow rate that the swale can manage while maintaining an approximate 0.5m freeboard.

The swales for the surface water pond system were not directly modelled as the flow characteristics are assumed to be similar

to the flow characteristics for the Landfill Catchment.

All of the swale designs are acceptable for managing the surface water as it passes through the various

sections of the swale system.

4.3.1.2 RORB Modelling

For the RORB model, the key characteristics of each catchment including the breakdown of the swale

design were recorded in the RORB program. However, the resulting peak flow rates were vastly lower

than the ones calculated using the Microsoft Excel algorithm. Therefore, the peak flow rates calculated

in the initial modelling were the adopted flow rates used in the final design of the swale system as

provided in Table 4-3.

4.3.2 Surface Water Ponds

4.3.2.1 Initial Modelling

The surface water pond sizing was initially conducted using a simple Microsoft Excel algorithm.

According to the IFD data from BOM, the total rainfall during a 1-in-100 storm with a 72hr duration is

436mm. Based on the surface area of the Landfill Catchment and an assumed runoff coefficient of

0.40, the minimum total capacity required is approximately 33,500m3. The rainfall that falls directly

into the swales is considered negligible.

4.3.2.2 RORB Modelling

The catchment features and swale system were inputted into the RORB model for the Landfill

Catchment. The model was then run under various IL and CL conditions, and considered both

3.0mm/hr and 6.0mm/hr for CL, as well as IL values between 30mm and 60mm, in line with the PSM

flood study. A summary of the results of the RORB analysis can be found in Table 4-5 and the detailed

calculations are provided in Appendix B.



Table 4-5: RORB Modelling Results for Pond Storage Requirements

Model Iteration IL (mm) CL (mm/hr) Inflow (m3)

1 60 6.0 22,700

2 60 3.0 39,100

3 50 6.0 24,300

4 50 3.0 40,800

5 40 6.0 25,800

6 40 3.0 42,400

7 30 6.0 25,900

8 30 3.0 42,500

In all four iterations with a CL of 6.0mm, the inflow volumes did not exceed 30,000m3, whereas for

iterations with a CL of 3.0mm, the inflow volumes were up to 42,500m3. The results utilising a CL of

3.0mm are higher than what is calculated in the Microsoft Excel modelling. Therefore, to allow for

conservativism and redundancy in the surface water management system, the highest inflow volume

of 42,500m3 was adopted for the design of the surface water ponds.

4.3.2.3 Surface Water Pond Design Characteristics

Table 4-6 contains the dimensions of the surface water pond system that will accommodate the

operational requirements determined in the initial modelling.

Table 4-6: Design Characteristics of Surface Water Pond System

Type of Pond Length

(m)

Width

(m)

Depth

(m)

Internal Pond

Side Slope

(V:H)

Surface

Area (m2)

Operational

Volume (m3)

Attenuation Pond 163.6 88.6 3.42 1:3 14,495 34,620

Infiltration/

Evaporation Pond # 1 91.0 71.0 1.76 1:3 6,461 5,611

Infiltration/

Evaporation Pond # 2 91.0 71.0 1.76 1:3 6,461 5,611

Notes: * The Operational Volume is calculated from the 0.5m freeboard level to the bottom level of each pond.

The total operational volume of the surface water pond system is approximately 45,842m3. To ensure

that no superficial surface water flows into the surface water pond system, each pond will be raised

0.5m above existing ground with 1:6 (V:H) external side slopes.

4.3.3 Other Associated Infrastructure

4.3.3.1 Rock Armouring

To mitigate scouring and maintain the integrity of the swale system, rock armouring will be installed

in strategic points across the system, specifically at steeper sections (slope gradient >0.020), junction



and intersection points. The methodology for determining the minimum stone diameter used in the

rock armouring and thickness of the armouring itself is outlined in Austroads Guide to Road Design

Part 5B: Drainage – Open Channels, Culverts and Floodways. The maximum velocity in each swale

section has already been calculated using the Microsoft Excel algorithm. Table 4-7 outlines the

proposed rock armouring details for the swale system, and the calculations are provided in Appendix

D.

Table 4-7: Rock Armouring Details for Swale System

Location Maximum

Velocity (m/s)

Bed Velocity

(m/s)

Stone Diameter

(mm)

Minimum

Thickness (mm)

Northern Catchment 3.01 2.107 150 225

North-eastern

Catchment 2.77

1.939 150 225

Southern Catchment 0.87 0.609 75 112.5

Landfill Catchment 2.17 1.519 75 112.5

Notes: The Maximum Velocity is the maximum velocity of the surface water through any part of the swale for the specified catchment.

The Bed Velocity is 0.70 times the Velocity through the swale.

The Minimum Thickness of the rock armouring is 1.5 times the largest stone diameter.

Any rock armouring that is required for swales within the surface water pond system will have the same details as the rock

armouring for the Landfill Catchment.

It is proposed that rock armouring for the Northern, North-eastern and Southern Catchment, swales,

will have a minimum thickness of 225mm with a minimum stone diameter of 150mm. Rock armouring

will need to be installed on junction points and on either end of the culverts.

For the Landfill Catchment swale, the rock armouring at the junction point with the inlet into the

surface water pond system must have a minimum thickness of 112.5mm with a minimum stone

diameter of 75mm.

The locations of proposed rock armouring and details are shown on Drawings G-100, G-101, G102 and

G-103, which are provided in Appendix A.

4.3.3.2 Culvert System

There are five intersection points where a site access road crosses over the swale system. In order to

manage these intersection points, a culvert system is required to safely divert the surface water under

the access roads. A Factor of Safety of at least 1.5 at the inlet was selected to account for partial

blockages and silt build-ups, prior to maintenance/clearing.

The methodology presented in Section 3 of the Austroads Part 5B: Drainage – Open Channels, Culverts

and Floodways Design Manual, in conjunction with the box culvert nomographs contained in Appendix

B, was applied. The detailed calculations have been provided in Appendix D of this Report.

Where the system constricts from a trapezoidal channel to a rectangular culvert and then back to a

trapezoidal channel, the Froude number for the upstream and downstream conditions was calculated

to determine if a hydraulic jump was likely to occur. A hydraulic jump arises when supercritical flow

(Froude number is greater than 1) representing fast, high energy flow transitions to subcritical flow



(Froude number less than 1). This event can cause significant erosion and scouring issues over time.

The maximum Froude number calculated using the Microsoft Excel algorithm was 0.27.

It was determined that the culvert required for Intersection Points #1, #3 and #4 is a set of 4 box

culverts that have an operational height of 0.9m and an operational width of 4.8m. For Intersection

Point #2, a set of 8 box culverts with an operational height of 0.9m and an operational width of 9.6m

will be required. Intersection Point #5 will require a set of 3 box culverts installed with an operational

height of 0.9m and an operational width of 3.6m.

4.3.4 Summary

4.3.4.1 Swale System

In order to determine the design of the swale system, several considerations need to be made. Each

swale is to be placed at the topographical low point of each catchment area. For sections of the swale

that have a slope gradient greater than 0.020, the bottom and sides of the swale will be lined with

riprap, or rock armouring, in order to slow the velocity of the water moving through the swale. This

will assist to mitigate scouring or erosion issues and maintain the integrity of the swale system. Where

a steeper section of swale is followed by a relatively flat slope gradient (less than 0.020), then an

additional 25m of the swale will be lined with riprap to mitigate scouring. If the swale has a significant

bend, then riprap will be placed along the length of that bend. As per Best Practice Landfill Standards,

the swale along the landfill catchment will be lined with a geomembrane liner. All other sections of

the swale system will be an unlined earth channel.

At junction points where the surface water from two swales is combined, scour protection measures

in the form of rock armouring will be required. At the intersection points between the swale system

and a Site access road, a box culvert system will be required to direct the water under the road.

The details for the swale system are illustrated in Drawings G-101, G-102 and G-103, which are

provided in Appendix A.

4.3.4.2 Surface Water Ponds

The perimeter drains along the landfill footprint will divert surface water into the surface water pond

system, which will consist of a lined attenuation pond and eventually two unlined

infiltration/evaporation ponds. The attenuation pond is designed to minimise the release of sediment

eroded from the landfill catchment to the downstream environment. The pond will be relatively deep

to encourage sedimentation before it feeds the excess surface water into one of two

infiltration/evaporation ponds. Only one infiltration/evaporation pond will be built during the early

stages of the Site operations followed by the construction of a second pond as the Site activities and

development footprint increases. The infiltration ponds will have shallow depths and large surface

areas to assist the rate of evaporation.

Cargo netting/roped egress points will be installed on the interior face of each lined pond which will

also be enclosed by a 1.8m high chain-link fence as a health and safety measure.



The infiltration ponds will also be constructed with overflows to enable controlled discharge of water

from storm events above the 1-in-100 year, 72hr storm durations.

The layout of the surface water pond system is demonstrated in Drawing G-100, which has been

provided in Appendix A.

4.4 Operational Management and Monitoring Strategy

To ensure environmental impacts are mitigated and the facility meets licence requirements,

appropriate operational management, especially for surface water, must be undertaken. Regular site

maintenance and repairs of drains and other associated surface water management infrastructure will

be undertaken. Site staff will particularly inspect the system for evidence of contamination, excessive

sedimentation and structural integrity of the system on a regular basis. Any ponding within the surface

depressions along the sand ridge northeast of the landfill development footprint will be managed via

a mobile pump when necessary. Further details of the operational management strategy are provided

in the Site’s Operational and Environmental Management Plan (OEMP).



5 Local Flood Risk Assessment

The PSM flood study concluded that the Site could be potentially affected by flooding in the

surrounding areas. To protect the Site from such events, it is proposed that a levee embankment will

be constructed along the southern boundary of the Site. Where the outside edge of the levee

embankment is likely to be effected by flooding, rock armouring will be installed to protect the

embankment from erosion and scouring caused by the regional flooding events.

5.1 Levee Embankment Design

The levee embankment will be constructed along the southern boundary of Site’s operational area to

protect the Site from regional flooding events. The levee will be constructed from compacted soil

excavated from the Site, and be compacted to a minimum of 95% Maximum Modified Dry Density

(MMDD). The embankment will be keyed into the existing ground profile along the centreline and

outer toe of the bund. Table 5-1 provides a summary of the key design characteristics of the proposed

levee embankment.

Table 5-1: Key Design Characteristics of the Levee Embankment

Outer External

Side Slope (V:H)

Maximum Bottom

Width (m)

Maximum Top

Width (m)

Length

(m)

Height

(m)

Volume of Soil

Required (m3)

1:6 20 2 1600 2 ~34,300

Rock armouring will be utilised on the outside edge of the levee embankment for scour prevention

and erosion resistance from regional flooding events.

According to the PSM flood study, the Site experiences low velocity (typically less than 0.50m/s) flow

at less than one metre depths even during significant weather events, due to a lack of defined surface

channels. The methodology for determining the minimum stone diameter used in the rock armouring

and thickness of the armouring itself is outlined in Austroads Guide to Road Design Part 5B: Drainage

– Open Channels, Culverts and Floodways, specifically Figure 2.22. Using the PSM flow velocity, Table

5-2 provides a summary of the minimum rock armouring requirements for the levee embankment

system.

Table 5-2: Minimum Rock Armouring Details for Levee Embankment

Bed Velocity (m/s) D50 Stone Diameter (mm) Minimum Thickness (mm)

0.50 50 75

The minimum thickness of the rock armouring for the levee embankment system is 75mm, using a

minimum stone size of 50mm in diameter. Calculations are presented in Appendix D.

In order to protect the integrity of the development area and allow for regional flood events above

the modelled scenario, a Factor of Safety of 3.5 has been applied to the flow velocity. It is therefore

proposed that rock armouring to the levee embankment will consist of a separation geotextile,

150mm granular filter layer and 225mm minimum thickness of well graded riprap (125mm maximum



stone diameter), placed to a height of up to 1.5m. Typical levee embankment construction details are

shown on Drawing G-103.

5.2 Design Review

PSM has undertaken a review of the surface water management design, and updated the regional

flood study model. With regards to the levee embankment, the proposed design was assessed against

a number of flood events, including 1 in 50 year, 1 in 100 year and 1 in 500 year for durations of 24

hours.

The surface water review and flood modelling by PSM is included in Appendix E.

A summary of the PSM modelling and review is presented as follows:

The levee embankment does not overtop at any point for any of the flood events, with the freeboard

to the top of the flood protection bund [levee embankment] in excess of 0.5m for all modelled events.

“Additionally, the velocity adjacent to the flood protection bund [levee embankment] is below 2m/s

(i.e. the typical erosional threshold presented in the Austroads Guide to Road Design), with velocities

typically less than 0.3m/s at the southern toe of the flood protection bund [levee embankment].”

Further, the PSM report states:

“Whilst optimisation of the flood protection bund [levee embankment] could be possible the

current design is still recommended:

o The additional freeboard allows some flexibility if a more extreme design event were

required by the regulator, and

o Whilst the velocity of the flood flow is typically less than 0.3 m/s the rip-rap protection

provided, will help protect against scour and erosion in small scale localised velocity

hotspots (which have not been picked the hydraulic modelling with a 10m grid size) and

improve the assets longevity. Provision of rip-rap protection along the entire flood

protection would be useful and is recommended for the segment to the east of 317,000

mE.”

Rock armouring will, therefore, be placed on the outside edge of the levee embankment at a minimum

from 317,000 mE, (eastwards to the site access road), for scour prevention and erosion resistance

from regional flooding events.



Figures

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Min der oo

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285,000

285,000

290,000

290,000

295,000

295,000

300,000

300,000

305,000

305,000

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315,000

315,000

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345,000

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,000

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,000

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,000

7,560

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,000

7,565

,000

7,570

,000

7,570

,000

7,575

,000

7,575

,000

7,580

,000

7,580

,000

7,585

,000

7,585

,000

7,590

,000

7,590

,000

7,595

,000

7,595

,000

7,600

,000

7,600

,000

LEGEND

© Talis Co nsu ltan ts P ty Ltd ("Talis") Copyright i n the drawi ngs, i nform at ion a nd datarecorded in th is docum ent ("th e in form ati on") is the property of Talis. T his docum ent andthe i nform ati on are solel y for the use of th e auth orised recipient andthis docu ment m ay not be used, transferred or reprodu ced in whole o r partfor any purpose other than that which it i s supp lied by Talis withoutwri tten consent. Talis m akes no representat ion, undertakes no duty an daccepts no responsibili ty to a ny th ird party who may use or rel y upon thi sdocu ment or the in form ati on.

Yanrey

PannawonnicaOnslow

Red HillCane River

0 40 80 120 16020km

LOCALITY

LOCALITY PLANSurface Water Management Plan

Pilbara Regional WasteManagement Facility

Lot 150 Onslow RoadTalandji, WA 6710

0 4 81 2 3Km

¤ Coor dinate S y stem : GDA 1994 MG A Zone 50Pro jection: Trans vers e Mer cator, Datum : GDA 1994

Reviewed:Checked:Prepared: Date:

Revision:

Sc ale @ A 3:1:200,000

Project No:

Data s our ce: Im ager y - Landgate, 2017. Roads - M ain Roads WA , 2017

Figure

01

Site Boundary

P: PO Box 454, Leederville WA 6903 | A: Level 1 660 Newcastle St, Leederville WA 6007 | T: 1300 251 070 | W: www.ta lisconsultants.com.au

E. PorterN King

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Onslow Rd

30

20

18

38

18

26

32

28

16

24 34

28

2222

36

30

26

20

16

26

24

24

14

26

24

16

16

30

32

14 26

26

3426

30

36

28

24

30

14

30

22

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28

30

283238

20

1616

28

22

24

22

1634

24

3832

36

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24

24

28

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26

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28 26

34

26

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36

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3214

32

18

2026

22

24

16

28

30

314,500

314,500

315,000

315,000

315,500

315,500

316,000

316,000

316,500

316,500

317,000

317,000

317,500

317,500

318,000

318,000

318,500

318,500

7,574

,000

7,574

,000

7,574

,500

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,500

7,575

,000

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,500

7,575

,500

7,576

,000

7,576

,000

7,576

,500

7,576

,500

7,577

,000

7,577

,000

7,577

,500

7,577

,500 LEGEND

© Tal is Co ns ul tants P ty L td ("Ta l is " ) C opy righ t in the d raw ings , in for m ation and d atarec ord ed in th is doc um e nt (" the in fo rm atio n") is t he pr opert y o f Ta l is . Th is d oc um en t andthe in fo rm at io n ar e s o le ly for the u s e of the a uthor ise d r ec ip ient a ndth is doc um ent m a y not be us ed, tr ans fer red or re produ c ed in w hole or pa rtfor a ny pur pos e o ther than t hat w hic h i t is s uppl ied by Tal is w i thoutwr i tten c o ns ent. Ta l is m ak es no r epres e ntation, unde rtak es no du ty andac c epts no res po ns ib i l it y to an y th i rd p arty w ho m ay u se or r e ly upo n th isdoc um e nt o r t he in form a tion.

Yanrey

PannawonnicaOnslow

Red HillCane River

0 40 80 120 16020km

LOCALITY

TOPOGRAPHYSurface Water Management Plan



0 125 250 375 500metres

¤ Co o rd in at e Sy st em : G D A 1 99 4 M G A Z on e 5 0Pro je ct io n: T r an sv e rs e M e rc a to r, Da tu m : G DA 1 99 4

Re vie we d:Ch ecked :Pre pa re d: Da te:

Re vision :

Sca le @ A 4:1: 20 ,0 0 0

Pro ject No:

Da ta s ou r ce : Im a g er y - L an d g at e , 2 0 18 . To p o gr a ph y - D en a d a Su rv ey s, 2 0 17

Figur

e 02

Site BoundaryElevation (mAHD)

P: PO Box 454, Leederv il le WA 6903 | A : Level 1 660 Newcastle St, Leederv il le W A 6007 | T: 1300 251 070 | W : www.ta lisc ons ultants.c om .au

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CA NER

I V E RA S H BU R TON

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QUEERBULLACLAYPAN

NARNEEYARRACLAYPAN

JABADDARPOOL

290,000

290,000

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LEGEND

© Tal is Co ns ul tants P ty L td ("Ta lis " ) C opy righ t in the dr aw ings , in for m ation and d atarec ord ed in th is doc um e nt (" the in fo rm atio n") is t he pr operty o f Ta l is . Th is d oc um en t andthe in fo rm at io n ar e s o le ly for t he us e of the a uthor is e d re c ip ient a ndth is doc um ent m a y not be us ed, tr ans fer red o r re produ c ed in w hole or pa rtfor an y pur pos e o ther than th at w hic h i t is s uppl ied by Tal is w i thoutwr i tten c o ns ent. Ta l is m ak es no re pres e ntation, under tak es n o du ty andac c epts no res po ns ib i l it y to any th i rd p arty w ho m ay us e or r e ly upon th isdoc um e nt o r th e in f orm a tio n.

Yanrey

PannawonnicaOnslow

Red HillCane River

0 40 80 120 16020km

LOCALITY

HYDROLOGYSurface Water Management Plan



¤ Co o rd in at e Sy st em : G D A 1 99 4 M G A Z on e 5 0Pro je ct io n: T r an sv e rs e M e rc a to r, Da tu m : G DA 1 99 4

Re vie we d:Ch ecked :Pre pa re d: Da te:

Re vision :

Sca le @ A 4:1: 30 0 ,0 0 0

Pro ject No:

Da ta s ou r ce : Im a g er y - L an d g at e, 2 0 17 . Ri ve rs , Pr oc la im e d A re a s - De p ar tm e n t of W at er , 20 1 7 . L a ke s - G eo s cie n ce Au st ra lia , 2 01 7 .

Figur

e 03

Site BoundaryRiversLakesSur face Water R esourceProclaim ed Area (RIWIAct)

P: PO Box 454, Leederv il le WA 6903 | A : Level 1 660 Newcastle St, Leederv il le WA 6007 | T: 1300 251 070 | W : www.ta lisc ons ultants.com .au

C. P aniz zaN K in g

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0 4 81 2 3Km

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AshburtonRiver

Onslow CoastAshburton

River

AshburtonRiver

Onslow Coast

Onslow Coast

Onslow Coast

285,000

285,000

290,000

290,000

295,000

295,000

300,000

300,000

305,000

305,000

310,000

310,000

315,000

315,000

320,000

320,000

325,000

325,000

330,000

330,000

335,000

335,000

340,000

340,000

345,000

345,000

7,555

,000

7,555

,000

7,560

,000

7,560

,000

7,565

,000

7,565

,000

7,570

,000

7,570

,000

7,575

,000

7,575

,000

7,580

,000

7,580

,000

7,585

,000

7,585

,000

7,590

,000

7,590

,000

7,595

,000

7,595

,000

7,600

,000

7,600

,000

LEGEND

© Talis Co nsu ltan ts P ty Ltd ("Talis") Copyright i n the drawi ngs, i nform at ion a nd datarecorded in th is docum ent ("th e in form ati on") is the property of Talis. T his docum ent andthe i nform ati on are solel y for the use of th e auth orised recipient andthis docu ment m ay not be used, transferred or reprodu ced in whole o r partfor any purpose other than that which it i s supp lied by Talis withoutwri tten consent. Talis m akes no representat ion, undertakes no duty an daccepts no responsibili ty to a ny th ird party who may use or rel y upon thi sdocu ment or the in form ati on.

Yanrey

PannawonnicaOnslow

Red HillCane River

0 40 80 120 16020km

LOCALITY

CATCHMENT AREASSurface Water Management Plan



¤ Coor dinate S y stem : GDA 1994 MG A Zone 50Pro jection: Trans vers e Mer cator, Datum : GDA 1994

Reviewed:Checked:Prepared: Date:

Revision:

Sc ale @ A 3:1:200,000

Project No:

Data s our ce: Im ager y - Landgate, 2017. Catc hments - Depar tment o f Water, 2016

Figure

04

Site BoundaryHydrographicSubcatchmentsBasin Name

Ashburton RiverOnslow Coast

P: PO Box 454, Leederville WA 6903 | A: Level 1 660 Newcastle St, Leederville WA 6007 | T: 1300 251 070 | W: www.ta lisconsultants.com.au

E. PorterN King

F Walker 13/09/2018TW18004

A

0 4 81 2 3Km



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Level 1 660 Newcastle Street,

Leederville WA 6007

PO Box 454, Leederville WA 6903

T: 1 3 0 0 2 5 1 0 7 0w w w . t a l i s c o n s u l t a n t s . c o m . au

ASSET MANAGEMENT

CIVIL ENGINEERING

ENVIRONMENTAL SERVICES

SPATIAL INTELLIGENCE

WASTE MANAGEMENT


Leederville WA 6007

PO Box 454, Leederville WA 6903T: 1 3 0 0 2 5 1 0 7 0w w w . t a l i s c o n s u l t a n t s . c o m . au

ASSET MANAGEMENT

CIVIL ENGINEERING



WASTE MANAGEMENT

Prin

te

d b

y A

rm

an

d B

este

r o

n 1

2.0

9.2

01

8 0

9:0

2 A

M


Leederville WA 6007

PO Box 454, Leederville WA 6903T: 1 3 0 0 2 5 1 0 7 0w w w . t a l i s c o n s u l t a n t s . c o m . au

ASSET MANAGEMENT

CIVIL ENGINEERING



WASTE MANAGEMENT

Prin

te

d b

y A

rm

an

d B

este

r o

n 0

5.0

9.2

01

8 0

4:4

8 P

M


Leederville WA 6007

PO Box 454, Leederville WA 6903

T: 1 3 0 0 2 5 1 0 7 0w w w . t a l i s c o n s u l t a n t s . c o m . au

ASSET MANAGEMENT

CIVIL ENGINEERING



WASTE MANAGEMENT



: RORB Modelling Results

Pond Storage_30IL_3CL RORBWin Output File ******************* Program version 6.32 (last updated 3rd September 2017) Copyright Monash University and Hydrology and Risk Consulting Date run: 28 Aug 2018 12:59

Vector file : \\server\talis\SECTIONS\Waste\PROJECTS\TW2018\TW18004 - Onslow Approval Documentation\Data\Surface Water\RORBWin\New Catchments\Area 4 Simulation\Area4-New2_Storage.catg Storm file : \\server\talis\SECTIONS\Waste\PROJECTS\TW2018\TW18004 - Onslow Approval Documentation\Data\Surface Water\RORBWin\New Catchments\Area 4 Simulation\Area4-New2_Storage_dr16ari7.stm Output information: Flows & all input data

Data checks: ************ Next data to be read & checked:

Catchment name & reach type flag Control vector & storage data Code no. 7 16.0 Sub-area areas Impervious flag Initial storm data Rainfall burst times Pluviograph 1 Sub-area rainfalls

Data check completed

Data: ****

Area4

Time data, in increments from initial time Area4: 72 hour 1% Design Storm Time increment (hours)= 3.00

Start Finish Rainfall times: 0 24

End of hyeto/hydrographs: 24 Duration of calculations: 70

Pluviograph data (time in incs, rainfall in mm, in increment following time shown)

1:Temporal pattern (% of depth Time 1 0 8.9 1 9.9 2 4.5 3 9.8 4 3.5 5 4.8 6 6.6 7 4.8 8 18.3 9 10.9 10 2.7 11 0.6 12 0.7 13 0.0 14 0.0 15 0.0 16 0.4

Page 1

Pond Storage_30IL_3CL 17 5.2 18 0.7 19 0.0 20 0.0 21 0.1 22 2.3 23 5.3

Total 100.0

DESIGN run control vector

Step Code Description 1 1 Add sub-area 'A' inflow & route thru normal storage 1 2 5 Route hydrograph thru normal storage 2 3 3 Store hydrograph from step 2; reset hydrograph to zero 4 1 Add sub-area 'B' inflow & route thru normal storage 3 5 5 Route hydrograph thru normal storage 4 6 4 Add h-graph ex step 3 to h-graph ex step 5 7 16.0 Route thru existing storage, Pond 8 0 **********End of control vector**********

Sub-area data

Sub- Area Dist. area km² km* A 1.61E-01 6.25E-01 B 2.90E-02 3.20E-01

Total 1.900E-01

For whole catchment ; Av. Dist., km* = 0.58 For interstation area 1; Av. Dist., km* = 0.58; ISA Factor = 1.000

* or other function of reach properties related to travel time

Normal storage data

Storage Length Rel. delay Type Slope no. km* time percent 1 0.1 0.190 Natural 2 0.5 0.242 Lined 0.167 3 0.1 0.182 Natural 4 0.2 0.018 Lined 6.772


Special storage data

Storage: Pond Initial water level at cease to flow elevation Storage-discharge reln.: Storage = 3600*0.829E+02*(disch)** 0.74 cub. m. Elevation (m) - Storage (m³) table 0.50 5.017E+03 1.00 1.044E+04 1.50 1.601E+04 2.00 2.181E+04 2.50 2.784E+04 3.00 3.410E+04

Input of parameters: ********************

Area4 DESIGN Run

Page 2

Pond Storage_30IL_3CL Area4: 72 hour 1% Design Storm Time increment = 3.00 hours

Constant loss model selected

Rainfall, mm, in time inc. following time shown Time Sub- Catch Area Incs ment A B

0 38.9 39 39 1 43.3 43 43 2 19.4 19 19 3 42.6 43 43 4 15.0 15 15 5 20.7 21 21 6 28.9 29 29 7 20.7 21 21 8 79.7 80 80 9 47.7 48 48 10 11.9 12 12 11 2.5 3 3 12 3.1 3 3 13 0.0 0 0 14 0.0 0 0 15 0.0 0 0 16 1.9 2 2 17 22.6 23 23 18 3.1 3 3 19 0.0 0 0 20 0.0 0 0 21 0.6 1 1 22 10.0 10 10 23 23.2 23 23

Tot.436.0 436 436 Pluvi. ref. no. 1 1

Rainfall-excess, mm, in time inc. following time shown Time Sub- Catch Area Incs ment A B

0 0.0 0 0 1 34.3 34 34 2 10.4 10 10 3 33.6 34 34 4 6.0 6 6 5 11.7 12 12 6 19.9 20 20 7 11.7 12 12 8 70.7 71 71 9 38.7 39 39 10 2.9 3 3 11 0.0 0 0 12 0.0 0 0 13 0.0 0 0 14 0.0 0 0 15 0.0 0 0 16 0.0 0 0 17 13.6 14 14 18 0.0 0 0 19 0.0 0 0 20 0.0 0 0 21 0.0 0 0 22 1.0 1 1 23 14.2 14 14

Tot.268.8 269 269

Page 3

Pond Storage_30IL_3CL

Routing results: **************** Area4 Area4: 72 hour 1% Design Storm DESIGN run no. 1

Parameters: kc = 0.90 m = 0.80

Loss parameters Initial loss (mm) Cont. loss (mm/h) 30.00 3.00

Results of routing through special storage Pond with ks = 0.8289E+02 & ms = 0.74 Peak elevation exceeds max. of elev.-stor. table, 3.00 Peak outflow = 0.07 m³/s Peak storage = 4.25E+04 m³

*** Special storage : Pond

Hydrograph Outflow Inflow Peak discharge,m³/s 0.072 1.040 Time to peak,h 33.0 27.0 Volume,m³ 3.25E+04 5.18E+04 Time to centroid,h 100. 26. Lag (c.m. to c.m.),h 76.3 2.5 Lag to peak,h 9.59 3.59

Hydrograph summary ******************

Site Description 01 Special storage : Pond - Outflow 02 Special storage : Pond - Inflow

Inc Time Hyd0001 Hyd0002 1 3.00 0.0000 0.0000 2 6.00 0.0000 0.0000 3 9.00 0.0015 0.4604 4 12.00 0.0061 0.3651 5 15.00 0.0114 0.3876 6 18.00 0.0170 0.3402 7 21.00 0.0200 0.0411 8 24.00 0.0237 0.4139 9 27.00 0.0290 0.2005 10 30.00 0.0410 1.0403 11 33.00 0.0621 0.9304 12 36.00 0.0719 0.0151 13 39.00 0.0708 0.0350 14 42.00 0.0695 0.0000 15 45.00 0.0678 0.0000 16 48.00 0.0662 0.0000 17 51.00 0.0646 0.0000 18 54.00 0.0631 0.0000 19 57.00 0.0636 0.1730 20 60.00 0.0653 0.0979 21 63.00 0.0649 0.0000 22 66.00 0.0634 0.0000 23 69.00 0.0619 0.0000 24 72.00 0.0606 0.0103 25 75.00 0.0616 0.1934 26 78.00 0.0635 0.0943 27 81.00 0.0631 0.0000 28 84.00 0.0616 0.0000 29 87.00 0.0602 0.0000 30 90.00 0.0588 0.0000 31 93.00 0.0574 0.0000 32 96.00 0.0561 0.0000 33 99.00 0.0548 0.0000 34 102.00 0.0536 0.0000 35 105.00 0.0524 0.0000

Page 4

Pond Storage_30IL_3CL 36 108.00 0.0512 0.0000 37 111.00 0.0501 0.0000 38 114.00 0.0490 0.0000 39 117.00 0.0479 0.0000 40 120.00 0.0468 0.0000 41 123.00 0.0458 0.0000 42 126.00 0.0448 0.0000 43 129.00 0.0439 0.0000 44 132.00 0.0429 0.0000 45 135.00 0.0420 0.0000 46 138.00 0.0411 0.0000 47 141.00 0.0403 0.0000 48 144.00 0.0394 0.0000 49 147.00 0.0386 0.0000 50 150.00 0.0378 0.0000 51 153.00 0.0370 0.0000 52 156.00 0.0363 0.0000 53 159.00 0.0355 0.0000 54 162.00 0.0348 0.0000 55 165.00 0.0341 0.0000 56 168.00 0.0334 0.0000 57 171.00 0.0327 0.0000 58 174.00 0.0321 0.0000 59 177.00 0.0315 0.0000 60 180.00 0.0308 0.0000 61 183.00 0.0302 0.0000 62 186.00 0.0296 0.0000 63 189.00 0.0291 0.0000 64 192.00 0.0285 0.0000 65 195.00 0.0280 0.0000 66 198.00 0.0274 0.0000 67 201.00 0.0269 0.0000 68 204.00 0.0264 0.0000 69 207.00 0.0259 0.0000 70 210.00 0.0254 0.0000 71 213.00 0.0250 0.0000

Page 5

Pond Storage_30IL_6CL RORBWin Output File ******************* Program version 6.32 (last updated 3rd September 2017) Copyright Monash University and Hydrology and Risk Consulting Date run: 27 Jun 2018 13:05

Vector file : \\server\talis\SECTIONS\Waste\PROJECTS\TW2018\TW18004 - Onslow Approval Documentation\Data\Storm Water\RORBWin\New Catchments\Area 4 Simulation\Area4.catg Storm file : \\SERVER\Talis\SECTIONS\Waste\PROJECTS\TW2018\TW18004 - Onslow Approval Documentation\Data\Storm Water\RORBWin\New Catchments\Area 4 Simulation\Area4_dr16ari7.stm Output information: Flows & all input data




Data: ****

Area4






Page 1


Total 100.0


Step Code Description 1 1 Add sub-area 'A' inflow & route thru normal storage 1 2 5 Route hydrograph thru normal storage 2 3 3 Store hydrograph from step 2; reset hydrograph to zero 4 1 Add sub-area 'B' inflow & route thru normal storage 3 5 4 Add h-graph ex step 3 to h-graph ex step 4 6 5 Route hydrograph thru normal storage 4 7 3 Store hydrograph from step 6; reset hydrograph to zero 8 1 Add sub-area 'C' inflow & route thru normal storage 5 9 4 Add h-graph ex step 7 to h-graph ex step 8 10 5 Route hydrograph thru normal storage 6 11 3 Store hydrograph from step 10; reset hydrograph to zero 12 1 Add sub-area 'D' inflow & route thru normal storage 7 13 4 Add h-graph ex step 11 to h-graph ex step 12 14 5 Route hydrograph thru normal storage 8 15 3 Store hydrograph from step 14; reset hydrograph to zero 16 1 Add sub-area 'E' inflow & route thru normal storage 9 17 4 Add h-graph ex step 15 to h-graph ex step 16 18 3 Store hydrograph from step 17; reset hydrograph to zero 19 1 Add sub-area 'F' inflow & route thru normal storage 10 20 4 Add h-graph ex step 18 to h-graph ex step 19 21 16.0 Route thru existing storage, Pond 22 0 **********End of control vector**********

Sub-area data

Sub- Area Dist. area km² km* A 2.80E-02 6.98E-01 B 2.80E-02 5.36E-01 C 2.80E-02 3.74E-01 D 2.80E-02 2.12E-01 E 2.80E-02 1.00E-01 F 2.80E-02 5.00E-02

Total 1.680E-01



Normal storage data

Storage Length Rel. delay Type Slope no. km* time percent 1 0.1 0.152 Natural 2 0.2 0.265 Unlined 0.149 3 0.1 0.152 Natural 4 0.2 0.265 Unlined 0.149 5 0.1 0.152 Natural 6 0.2 0.265 Unlined 0.149 7 0.1 0.152 Natural 8 0.2 0.265 Unlined 0.149 9 0.1 0.163 Unlined 0.149 10 0.1 0.152 Natural

Page 2

Pond Storage_30IL_6CL * or other function of reach properties related to travel time




Area4 DESIGN Run Area4: 72 hour 1% Design Storm Time increment = 3.00 hours


Rainfall, mm, in time inc. following time shown Time Sub- Catch Area Incs ment A B C D E F

0 38.9 39 39 39 39 39 39 1 43.3 43 43 43 43 43 43 2 19.4 19 19 19 19 19 19 3 42.6 43 43 43 43 43 43 4 15.0 15 15 15 15 15 15 5 20.7 21 21 21 21 21 21 6 28.9 29 29 29 29 29 29 7 20.7 21 21 21 21 21 21 8 79.7 80 80 80 80 80 80 9 47.7 48 48 48 48 48 48 10 11.9 12 12 12 12 12 12 11 2.5 3 3 3 3 3 3 12 3.1 3 3 3 3 3 3 13 0.0 0 0 0 0 0 0 14 0.0 0 0 0 0 0 0 15 0.0 0 0 0 0 0 0 16 1.9 2 2 2 2 2 2 17 22.6 23 23 23 23 23 23 18 3.1 3 3 3 3 3 3 19 0.0 0 0 0 0 0 0 20 0.0 0 0 0 0 0 0 21 0.6 1 1 1 1 1 1 22 10.0 10 10 10 10 10 10 23 23.2 23 23 23 23 23 23

Tot.436.0 436 436 436 436 436 436 Pluvi. ref. no. 1 1 1 1 1 1

Rainfall-excess, mm, in time inc. following time shown Time Sub- Catch Area Incs ment A B C D E F

0 0.0 0 0 0 0 0 0 1 25.3 25 25 25 25 25 25 2 1.4 1 1 1 1 1 1 3 24.6 25 25 25 25 25 25

Page 3

Pond Storage_30IL_6CL 4 0.0 0 0 0 0 0 0 5 2.7 3 3 3 3 3 3 6 10.9 11 11 11 11 11 11 7 2.7 3 3 3 3 3 3 8 61.7 62 62 62 62 62 62 9 29.7 30 30 30 30 30 30 10 0.0 0 0 0 0 0 0 11 0.0 0 0 0 0 0 0 12 0.0 0 0 0 0 0 0 13 0.0 0 0 0 0 0 0 14 0.0 0 0 0 0 0 0 15 0.0 0 0 0 0 0 0 16 0.0 0 0 0 0 0 0 17 4.6 5 5 5 5 5 5 18 0.0 0 0 0 0 0 0 19 0.0 0 0 0 0 0 0 20 0.0 0 0 0 0 0 0 21 0.0 0 0 0 0 0 0 22 0.0 0 0 0 0 0 0 23 5.2 5 5 5 5 5 5

Tot.168.8 169 169 169 169 169 169




Results of routing through special storage Pond with ks = 0.8289E+02 & ms = 0.74 Peak elevation= 2.34 m Peak outflow = 0.04 m³/s Peak storage = 2.59E+04 m³





Inc Time Hyd0001 Hyd0002 1 3.00 0.0000 0.0000 2 6.00 0.0000 0.0000 3 9.00 0.0007 0.2458 4 12.00 0.0027 0.1986 5 15.00 0.0049 0.2025 6 18.00 0.0073 0.1861 7 21.00 0.0087 0.0246 8 24.00 0.0096 0.1171 9 27.00 0.0111 0.1051 10 30.00 0.0169 0.6486 11 33.00 0.0292 0.7422

Page 4

Pond Storage_30IL_6CL 12 36.00 0.0368 0.0792 13 39.00 0.0369 0.0000 14 42.00 0.0361 0.0000 15 45.00 0.0354 0.0000 16 48.00 0.0347 0.0000 17 51.00 0.0340 0.0000 18 54.00 0.0333 0.0000 19 57.00 0.0330 0.0363 20 60.00 0.0330 0.0360 21 63.00 0.0328 0.0052 22 66.00 0.0322 0.0000 23 69.00 0.0316 0.0000 24 72.00 0.0309 0.0000 25 75.00 0.0307 0.0417 26 78.00 0.0309 0.0407 27 81.00 0.0308 0.0054 28 84.00 0.0302 0.0000 29 87.00 0.0297 0.0000 30 90.00 0.0291 0.0000 31 93.00 0.0285 0.0000 32 96.00 0.0280 0.0000 33 99.00 0.0274 0.0000 34 102.00 0.0269 0.0000 35 105.00 0.0264 0.0000 36 108.00 0.0259 0.0000 37 111.00 0.0254 0.0000 38 114.00 0.0250 0.0000 39 117.00 0.0245 0.0000 40 120.00 0.0240 0.0000 41 123.00 0.0236 0.0000 42 126.00 0.0232 0.0000 43 129.00 0.0228 0.0000 44 132.00 0.0223 0.0000 45 135.00 0.0219 0.0000 46 138.00 0.0215 0.0000 47 141.00 0.0212 0.0000 48 144.00 0.0208 0.0000 49 147.00 0.0204 0.0000 50 150.00 0.0201 0.0000 51 153.00 0.0197 0.0000 52 156.00 0.0194 0.0000 53 159.00 0.0190 0.0000 54 162.00 0.0187 0.0000 55 165.00 0.0184 0.0000 56 168.00 0.0181 0.0000 57 171.00 0.0178 0.0000 58 174.00 0.0175 0.0000 59 177.00 0.0172 0.0000 60 180.00 0.0169 0.0000 61 183.00 0.0166 0.0000 62 186.00 0.0163 0.0000 63 189.00 0.0160 0.0000 64 192.00 0.0158 0.0000 65 195.00 0.0155 0.0000 66 198.00 0.0153 0.0000 67 201.00 0.0150 0.0000 68 204.00 0.0148 0.0000 69 207.00 0.0145 0.0000 70 210.00 0.0143 0.0000 71 213.00 0.0141 0.0000

Page 5






Data: ****

Area4






Page 1


Total 100.0



Sub-area data


Total 1.900E-01



Normal storage data






Area4 DESIGN Run

Page 2




0 38.9 39 39 1 43.3 43 43 2 19.4 19 19 3 42.6 43 43 4 15.0 15 15 5 20.7 21 21 6 28.9 29 29 7 20.7 21 21 8 79.7 80 80 9 47.7 48 48 10 11.9 12 12 11 2.5 3 3 12 3.1 3 3 13 0.0 0 0 14 0.0 0 0 15 0.0 0 0 16 1.9 2 2 17 22.6 23 23 18 3.1 3 3 19 0.0 0 0 20 0.0 0 0 21 0.6 1 1 22 10.0 10 10 23 23.2 23 23

Tot.436.0 436 436 Pluvi. ref. no. 1 1


0 0.0 0 0 1 33.2 33 33 2 10.4 10 10 3 33.6 34 34 4 6.0 6 6 5 11.7 12 12 6 19.9 20 20 7 11.7 12 12 8 70.7 71 71 9 38.7 39 39 10 2.9 3 3 11 0.0 0 0 12 0.0 0 0 13 0.0 0 0 14 0.0 0 0 15 0.0 0 0 16 0.0 0 0 17 13.6 14 14 18 0.0 0 0 19 0.0 0 0 20 0.0 0 0 21 0.0 0 0 22 1.0 1 1 23 14.2 14 14

Tot.267.7 268 268

Page 3










Inc Time Hyd0001 Hyd0002 1 3.00 0.0000 0.0000 2 6.00 0.0000 0.0000 3 9.00 0.0015 0.4453 4 12.00 0.0059 0.3590 5 15.00 0.0111 0.3916 6 18.00 0.0167 0.3375 7 21.00 0.0197 0.0427 8 24.00 0.0234 0.4131 9 27.00 0.0287 0.2010 10 30.00 0.0407 1.0402 11 33.00 0.0617 0.9304 12 36.00 0.0715 0.0152 13 39.00 0.0704 0.0349 14 42.00 0.0691 0.0000 15 45.00 0.0674 0.0000 16 48.00 0.0658 0.0000 17 51.00 0.0643 0.0000 18 54.00 0.0628 0.0000 19 57.00 0.0633 0.1730 20 60.00 0.0650 0.0979 21 63.00 0.0646 0.0000 22 66.00 0.0631 0.0000 23 69.00 0.0616 0.0000 24 72.00 0.0603 0.0103 25 75.00 0.0613 0.1934 26 78.00 0.0632 0.0943 27 81.00 0.0628 0.0000 28 84.00 0.0614 0.0000 29 87.00 0.0599 0.0000 30 90.00 0.0585 0.0000 31 93.00 0.0572 0.0000 32 96.00 0.0559 0.0000 33 99.00 0.0546 0.0000 34 102.00 0.0534 0.0000 35 105.00 0.0522 0.0000

Page 4


Page 5






Data: ****

Area4






Page 1


Total 100.0



Sub-area data


Total 1.680E-01



Normal storage data


Page 2








0 38.9 39 39 39 39 39 39 1 43.3 43 43 43 43 43 43 2 19.4 19 19 19 19 19 19 3 42.6 43 43 43 43 43 43 4 15.0 15 15 15 15 15 15 5 20.7 21 21 21 21 21 21 6 28.9 29 29 29 29 29 29 7 20.7 21 21 21 21 21 21 8 79.7 80 80 80 80 80 80 9 47.7 48 48 48 48 48 48 10 11.9 12 12 12 12 12 12 11 2.5 3 3 3 3 3 3 12 3.1 3 3 3 3 3 3 13 0.0 0 0 0 0 0 0 14 0.0 0 0 0 0 0 0 15 0.0 0 0 0 0 0 0 16 1.9 2 2 2 2 2 2 17 22.6 23 23 23 23 23 23 18 3.1 3 3 3 3 3 3 19 0.0 0 0 0 0 0 0 20 0.0 0 0 0 0 0 0 21 0.6 1 1 1 1 1 1 22 10.0 10 10 10 10 10 10 23 23.2 23 23 23 23 23 23

Tot.436.0 436 436 436 436 436 436 Pluvi. ref. no. 1 1 1 1 1 1


0 0.0 0 0 0 0 0 0 1 24.2 24 24 24 24 24 24 2 1.4 1 1 1 1 1 1 3 24.6 25 25 25 25 25 25

Page 3


Tot.167.7 168 168 168 168 168 168



Loss parameters Initial loss (mm) Cont. loss (mm/h)40.00 6.00



Hydrograph Outflow Inflow

Peak discharge,m³/s 0.0366 0.7422 Time to peak,h 36.0 30.0 Volume,m³ 1.65E+04 2.91E+04 Time to centroid,h 102. 25. Lag (c.m. to c.m.),h 79.8 2.6 Lag to peak,h 13.8 7.8



Inc Time Hyd0001 Hyd0002 1 3.00 0.0000 0.0000 2 6.00 0.0000 0.0000 3 9.00 0.0006 0.2346 4 12.00 0.0025 0.1913 5 15.00 0.0047 0.2050 6 18.00 0.0071 0.1854 7 21.00 0.0085 0.0238 8 24.00 0.0093 0.1173 9 27.00 0.0108 0.1051 10 30.00 0.0167 0.6486 11 33.00 0.0289 0.7422

Page 4


Page 5






Data: ****

Area4






Page 1


Total 100.0



Sub-area data


Total 1.900E-01



Normal storage data






Area4 DESIGN Run

Page 2




0 38.9 39 39 1 43.3 43 43 2 19.4 19 19 3 42.6 43 43 4 15.0 15 15 5 20.7 21 21 6 28.9 29 29 7 20.7 21 21 8 79.7 80 80 9 47.7 48 48 10 11.9 12 12 11 2.5 3 3 12 3.1 3 3 13 0.0 0 0 14 0.0 0 0 15 0.0 0 0 16 1.9 2 2 17 22.6 23 23 18 3.1 3 3 19 0.0 0 0 20 0.0 0 0 21 0.6 1 1 22 10.0 10 10 23 23.2 23 23

Tot.436.0 436 436 Pluvi. ref. no. 1 1


0 0.0 0 0 1 23.2 23 23 2 10.4 10 10 3 33.6 34 34 4 6.0 6 6 5 11.7 12 12 6 19.9 20 20 7 11.7 12 12 8 70.7 71 71 9 38.7 39 39 10 2.9 3 3 11 0.0 0 0 12 0.0 0 0 13 0.0 0 0 14 0.0 0 0 15 0.0 0 0 16 0.0 0 0 17 13.6 14 14 18 0.0 0 0 19 0.0 0 0 20 0.0 0 0 21 0.0 0 0 22 1.0 1 1 23 14.2 14 14

Tot.257.7 258 258

Page 3










Inc Time Hyd0001 Hyd0002 1 3.00 0.0000 0.0000 2 6.00 0.0000 0.0000 3 9.00 0.0009 0.3053 4 12.00 0.0039 0.2996 5 15.00 0.0085 0.4304 6 18.00 0.0140 0.3121 7 21.00 0.0167 0.0576 8 24.00 0.0204 0.4056 9 27.00 0.0256 0.2048 10 30.00 0.0374 1.0388 11 33.00 0.0581 0.9306 12 36.00 0.0679 0.0161 13 39.00 0.0668 0.0336 14 42.00 0.0656 0.0000 15 45.00 0.0641 0.0000 16 48.00 0.0626 0.0000 17 51.00 0.0611 0.0000 18 54.00 0.0597 0.0000 19 57.00 0.0603 0.1730 20 60.00 0.0621 0.0979 21 63.00 0.0618 0.0000 22 66.00 0.0603 0.0000 23 69.00 0.0589 0.0000 24 72.00 0.0577 0.0103 25 75.00 0.0587 0.1934 26 78.00 0.0607 0.0943 27 81.00 0.0604 0.0000 28 84.00 0.0590 0.0000 29 87.00 0.0576 0.0000 30 90.00 0.0563 0.0000 31 93.00 0.0550 0.0000 32 96.00 0.0538 0.0000 33 99.00 0.0526 0.0000 34 102.00 0.0514 0.0000 35 105.00 0.0502 0.0000

Page 4


Page 5






Data: ****

Area4






Page 1


Total 100.0



Sub-area data


Total 1.680E-01



Normal storage data


Page 2








0 38.9 39 39 39 39 39 39 1 43.3 43 43 43 43 43 43 2 19.4 19 19 19 19 19 19 3 42.6 43 43 43 43 43 43 4 15.0 15 15 15 15 15 15 5 20.7 21 21 21 21 21 21 6 28.9 29 29 29 29 29 29 7 20.7 21 21 21 21 21 21 8 79.7 80 80 80 80 80 80 9 47.7 48 48 48 48 48 48 10 11.9 12 12 12 12 12 12 11 2.5 3 3 3 3 3 3 12 3.1 3 3 3 3 3 3 13 0.0 0 0 0 0 0 0 14 0.0 0 0 0 0 0 0 15 0.0 0 0 0 0 0 0 16 1.9 2 2 2 2 2 2 17 22.6 23 23 23 23 23 23 18 3.1 3 3 3 3 3 3 19 0.0 0 0 0 0 0 0 20 0.0 0 0 0 0 0 0 21 0.6 1 1 1 1 1 1 22 10.0 10 10 10 10 10 10 23 23.2 23 23 23 23 23 23

Tot.436.0 436 436 436 436 436 436 Pluvi. ref. no. 1 1 1 1 1 1


0 0.0 0 0 0 0 0 0 1 14.2 14 14 14 14 14 14 2 1.4 1 1 1 1 1 1 3 24.6 25 25 25 25 25 25

Page 3


Tot.157.7 158 158 158 158 158 158









Inc Time Hyd0001 Hyd0002 1 3.00 0.0000 0.0000 2 6.00 0.0000 0.0000 3 9.00 0.0003 0.1316 4 12.00 0.0012 0.1211 5 15.00 0.0029 0.2277 6 18.00 0.0052 0.1797 7 21.00 0.0064 0.0157 8 24.00 0.0072 0.1192 9 27.00 0.0086 0.1046 10 30.00 0.0142 0.6487 11 33.00 0.0261 0.7423

Page 4


Page 5






Data: ****

Area4






Page 1


Total 100.0



Sub-area data


Total 1.900E-01



Normal storage data






Area4 DESIGN Run

Page 2




0 38.9 39 39 1 43.3 43 43 2 19.4 19 19 3 42.6 43 43 4 15.0 15 15 5 20.7 21 21 6 28.9 29 29 7 20.7 21 21 8 79.7 80 80 9 47.7 48 48 10 11.9 12 12 11 2.5 3 3 12 3.1 3 3 13 0.0 0 0 14 0.0 0 0 15 0.0 0 0 16 1.9 2 2 17 22.6 23 23 18 3.1 3 3 19 0.0 0 0 20 0.0 0 0 21 0.6 1 1 22 10.0 10 10 23 23.2 23 23

Tot.436.0 436 436 Pluvi. ref. no. 1 1


0 0.0 0 0 1 13.2 13 13 2 10.4 10 10 3 33.6 34 34 4 6.0 6 6 5 11.7 12 12 6 19.9 20 20 7 11.7 12 12 8 70.7 71 71 9 38.7 39 39 10 2.9 3 3 11 0.0 0 0 12 0.0 0 0 13 0.0 0 0 14 0.0 0 0 15 0.0 0 0 16 0.0 0 0 17 13.6 14 14 18 0.0 0 0 19 0.0 0 0 20 0.0 0 0 21 0.0 0 0 22 1.0 1 1 23 14.2 14 14

Tot.247.7 248 248

Page 3




Loss parameters Initial loss (mm) Cont. loss (mm/h)60.00 3.00



Hydrograph Outflow Inflow

Peak discharge,m³/s 0.064 1.037 Time to peak,h 33.0 27.0 Volume,m³ 2.95E+04 4.78E+04 Time to centroid,h 101. 28. Lag (c.m. to c.m.),h 76.2 2.6 Lag to peak,h 7.99 1.99



Inc Time Hyd0001 Hyd0002 1 3.00 0.0000 0.0000 2 6.00 0.0000 0.0000 3 9.00 0.0004 0.1682 4 12.00 0.0021 0.2355 5 15.00 0.0061 0.4714 6 18.00 0.0113 0.2850 7 21.00 0.0139 0.0735 8 24.00 0.0176 0.3974 9 27.00 0.0226 0.2091 10 30.00 0.0341 1.0372 11 33.00 0.0545 0.9307 12 36.00 0.0642 0.0171 13 39.00 0.0633 0.0320 14 42.00 0.0621 0.0000 15 45.00 0.0607 0.0000 16 48.00 0.0593 0.0000 17 51.00 0.0579 0.0000 18 54.00 0.0566 0.0000 19 57.00 0.0573 0.1730 20 60.00 0.0591 0.0979 21 63.00 0.0589 0.0000 22 66.00 0.0575 0.0000 23 69.00 0.0562 0.0000 24 72.00 0.0550 0.0103 25 75.00 0.0561 0.1934 26 78.00 0.0581 0.0943 27 81.00 0.0579 0.0000 28 84.00 0.0565 0.0000 29 87.00 0.0552 0.0000 30 90.00 0.0540 0.0000 31 93.00 0.0528 0.0000 32 96.00 0.0516 0.0000 33 99.00 0.0504 0.0000 34 102.00 0.0493 0.0000 35 105.00 0.0482 0.0000

Page 4


Page 5






Data: ****

Area4






Page 1


Total 100.0



Sub-area data


Total 1.680E-01



Normal storage data


Page 2








0 38.9 39 39 39 39 39 39 1 43.3 43 43 43 43 43 43 2 19.4 19 19 19 19 19 19 3 42.6 43 43 43 43 43 43 4 15.0 15 15 15 15 15 15 5 20.7 21 21 21 21 21 21 6 28.9 29 29 29 29 29 29 7 20.7 21 21 21 21 21 21 8 79.7 80 80 80 80 80 80 9 47.7 48 48 48 48 48 48 10 11.9 12 12 12 12 12 12 11 2.5 3 3 3 3 3 3 12 3.1 3 3 3 3 3 3 13 0.0 0 0 0 0 0 0 14 0.0 0 0 0 0 0 0 15 0.0 0 0 0 0 0 0 16 1.9 2 2 2 2 2 2 17 22.6 23 23 23 23 23 23 18 3.1 3 3 3 3 3 3 19 0.0 0 0 0 0 0 0 20 0.0 0 0 0 0 0 0 21 0.6 1 1 1 1 1 1 22 10.0 10 10 10 10 10 10 23 23.2 23 23 23 23 23 23

Tot.436.0 436 436 436 436 436 436 Pluvi. ref. no. 1 1 1 1 1 1


0 0.0 0 0 0 0 0 0 1 4.2 4 4 4 4 4 4 2 1.4 1 1 1 1 1 1 3 24.6 25 25 25 25 25 25

Page 3


Tot.147.7 148 148 148 148 148 148









Inc Time Hyd0001 Hyd0002 1 3.00 0.0000 0.0000 2 6.00 0.0000 0.0000 3 9.00 0.0000 0.0333 4 12.00 0.0002 0.0463 5 15.00 0.0013 0.2494 6 18.00 0.0034 0.1744 7 21.00 0.0044 0.0075 8 24.00 0.0051 0.1219 9 27.00 0.0065 0.1035 10 30.00 0.0118 0.6490 11 33.00 0.0233 0.7423

Page 4


Page 5



: Surface Water Drainage

and Pond System Design Calculations

Shire of Ashburton


Stormwater Drainage: Inputs

South -21.6540East 115.1350

Duration 63% 50% 20% 10% 5% 2% 1% 0.5% 0.2% 0.1% 0.05% Duration 63% 50% 20% 10% 5% 2% 1% 0.5% 0.2% 0.1% 0.05%

0.5 1:1 1:2 1:5 1:10 1:20 1:50 1:100 1:200 1:500 1:1000 1:2000 1:1 1:2 1:5 1:10 1:20 1:50 1:100 1:200 1:500 1:1000 1:20001 min 0.017 1.67 1.98 2.97 3.67 4.36 5.29 6.02 1 min 100 119 178 219 260 316 3602 min 0.033 2.74 3.25 4.82 5.89 6.93 8.44 9.67 2 min 82.4 97.2 144 176 207 254 2943 min 0.050 3.88 4.6 6.85 8.4 9.92 12.1 13.8 3 min 77.8 92 137 168 198 243 2794 min 0.067 4.97 5.89 8.81 10.8 12.8 15.6 17.8 4 min 74.8 88.4 132 162 192 235 2705 min 0.083 5.99 7.1 10.6 13.1 15.5 18.9 21.6 5 min 72 85.2 127 157 186 227 26010 min 0.167 10.1 11.9 17.9 22.1 26.3 31.9 36.2 10 min 60.4 71.5 107 132 157 191 21715 min 0.25 13 15.3 23 28.4 33.7 40.9 46.4 15 min 51.9 61.3 91.8 113 135 163 18530 min 0.5 18.4 21.8 32.7 40.2 47.7 57.9 65.7 30 min 36.9 43.7 65.2 80.3 95.4 116 1311 hour 1 24.3 28.8 43.4 53.5 63.6 77.4 88.3 1 hour 24.4 29 43.5 53.6 63.7 77.8 88.92 hour 2 30.7 36.8 56.3 70 83.8 103 118 2 hour 15.6 18.6 28.4 35.3 42.3 52.1 603 hour 3 35 42.2 65.6 82.3 99.2 123 142 3 hour 11.9 14.3 22.2 27.8 33.5 41.6 48.26 hour 6 43.7 53.5 85.9 110 134 169 197 6 hour 7.5 9.16 14.7 18.7 23 28.8 33.512 hour 12 54.6 67.8 113 146 182 231 272 12 hour 4.71 5.83 9.68 12.6 15.6 19.8 23.224 hour 24 67 84.2 143 188 235 301 355 426 515 589 670 24 hour 2.89 3.62 6.15 8.06 10.1 12.9 15.2 17.7 21.4 24.5 27.948 hour 48 78.8 99.5 170 222 278 355 419 493 592 675 764 48 hour 1.69 2.13 3.62 4.74 5.92 7.57 8.96 10.3 12.3 14.1 15.972 hour 72 84.2 106 180 234 291 370 436 509 609 692 782 72 hour 1.19 1.51 2.55 3.31 4.11 5.25 6.23 7.06 8.46 9.61 10.996 hour 96 86.9 110 185 239 295 374 440 515 616 699 788 96 hour 0.923 1.16 1.95 2.53 3.11 3.97 4.73 5.37 6.41 7.28 8.21120 hour 120 88.5 112 187 241 296 375 441 520 622 705 795 120 hour 0.751 0.944 1.58 2.03 2.5 3.18 3.79 4.34 5.18 5.88 6.62144 hour 144 89.3 113 188 242 297 375 441 526 629 713 804 144 hour 0.632 0.795 1.33 1.7 2.09 2.65 3.16 3.65 4.37 4.95 5.59168 hour 168 89.9 113 189 243 298 376 442 533 637 723 816 168 hour 0.547 0.687 1.14 1.47 1.8 2.28 2.72 3.17 3.79 4.31 4.86

ARI in yearsCoefficient

A

Coefficient

B

Coefficient

C

Coefficient

D

Coefficient

E

Coefficient

F

Coefficient

G1 3.11E+00 -6.66E-01 -7.89E-02 9.57E-03 4.33E-03 -4.95E-04 -8.02E-05

(Coefficients Tab) 2 3.42E+00 -6.57E-01 -7.59E-02 1.04E-02 3.90E-03 -6.02E-04 -4.97E-05

OBSOLETE 5 3.83E+00 -6.25E-01 -6.73E-02 1.02E-02 3.05E-03 -6.28E-04 -1.98E-05

10 4.03E+00 -6.08E-01 -6.29E-02 1.02E-02 2.66E-03 -6.36E-04 -8.81E-06

20 4.23E+00 -5.95E-01 -5.88E-02 1.04E-02 2.20E-03 -6.75E-04 1.16E-05

50 4.47E+00 -5.80E-01 -5.48E-02 1.02E-02 1.83E-03 -6.79E-04 2.27E-05

100 4.62E+00 -5.69E-01 -5.18E-02 1.02E-02 1.53E-03 -6.90E-04 3.32E-05

Unit

59370 m2

Runoff Coefficient 1 = Sandy Soil, Flat, 5 - 10% 0.4

132620 m2


359200 m2


190200 m2


0.40

2.1 Swale #1: Area 1 (Northern)

Value Unit

Overland Flow (over waste mass)

100.00 m

7.46 mAHD

0.075 m/m

Kerby's Roughness Factor =Smooth bare soil 0.10

7.77 min

K=constant; =1.44 for SI

150.00 m L=flow length (m) **Source for Design Input data from AutoCAD Drawing

1.32 mAHD N=Kerby's roughness

0.009 m/m

5.71 min

Manning's, n = Earth channel - clean 0.022 K=constant; =0.0195 for SI

L=flow length (m)

290.00 m S=slope (m/m)

15.42 mAHD

0.053 m/m

4.75 min

Manning's, n = Earth channel - stony, cobbles 0.035 K=constant; =0.0195 for SI

L=flow length (m)


0.88 mAHD

0.002 m/m

27.46 min


45.69 min L=flow length (m)

S=slope (m/m)

2.2 Swale #2: Area 2 (Eastern)

Value Unit


75.00 m

8.59 mAHD

0.115


6.14 min


140.00 m L=flow length (m)


0.017

4.17 min


L=flow length (m)


11.60 mAHD

0.039

5.41 min

Manning's, n = Earth channel - stony, cobbles 0.035 K=constant; =0.0195 for SI

L=flow length (m)


0.59 mAHD

0.002

19.71 min



S=slope (m/m)

2.3 Swale #3: Area 3 (Southern)

Value Unit


250.00 m

1.18 mAHD

0.005


22.79 min




0.001

65.26 min



S=slope (m/m)

2.4 Swale #4: Area 4 (Landfill)

Value Unit


210.00 m

14.56 mAHD

0.069

Kerby's Roughness Factor =Poor grass/rough bare soil 0.20

15.45 min




0.002

36.64 min

Manning's, n = Plastic 0.009 K=constant; =0.0195 for SI


S=slope (m/m)

Channel Flow (through swale) A

Channel Flow (through swale) B - Steep

Channel Flow (through swale) A


Channel Flow (through swale)

Tc-ch = K*(L^0.770)*(S^-0.385)

Flow Length

ΔRL

Slope

Concentrated Flow, Tc-c

Flow Length

ΔRL

Slope

Time of concentration, Tc-ch Tc-ch = K*(L^0.770)*(S^-0.385)

Channel Flow (through swale)

Time of concentration, Tc-ch

Channel Flow (through swale) C

Flow Length

ΔRL

Slope

Intensity (mm/hr)

Intensity-Frequency-Duration Data

Flow Length

ΔRL

Slope Slope = ΔRL/ΔFlow Length

Overland Flow, Tc-o Tc-o = K*((L*N)^0.467)*(S^-0.235)

Slope

Overland Flow, Tc-o

Flow Length

ΔRL

Flow Length

ΔRL

Slope

Location

Rainfall (mm)

http://www.bom.gov.au/water/designRainfalls/revised-ifd/?year=2016

Annual Exceedance Probability

Total Flow Time, Tc (min)

Concentrated Flow, Tc-c Tc-ch = K*(L^0.770)*(S^-0.385)


ΔRL

Flow Length

ΔRL

Slope

Overland Flow, Tc-o

Flow Length

1 - North Catchment

Composite Runoff Coefficient, C

Co-ordinateshttps://www.google.com.au/maps

Area 2

Area 3

Area 4

Note:

2 - North-West Catchment

3 - South-West Catchment

4 - Landfill Catchment

Area 1

Fill in yellow fields

= Final values

Description

Onslow Road Landfill, Onslow

AR&R87 IFDs

1. Pond Design Inputs

http://www.bom.gov.au/hydro/has/cdirswebx/cdirswebx.shtml

2. Swale Design Inputs

Flow Length

ΔRL

Slope

Time of concentration, Tc-o

Tc-ch = K*(L^0.770)*(S^-0.385)

Equations (reference below)

http://onlinemanuals.txdot.gov/txdotmanuals/hyd/time_of_concentration.htm

Slope = ΔRL/ΔFlow Length

ΔRL

Slope


Tc-o = K*((L*N)^0.467)*(S^-0.235)

Concentrated Flow, Tc-c


Flow Length

ΔRL

Slope

Tc-o = K*((L*N)^0.467)*(S^-0.235)

Flow Length

Tc-ch = K*(L^0.770)*(S^-0.385)

Catchment Locations


Tc-o = K*((L*N)^0.467)*(S^-0.235)

Tc-ch = K*(L^0.770)*(S^-0.385) Concentrated Flow, Tc-c


Slope

Time of concentration, Tc-ch Tc-ch = K*(L^0.770)*(S^-0.385)


Flow Length

ΔRL

Slope

Concentrated Flow, Tc-c Tc-ch = K*(L^0.770)*(S^-0.385)

TW18004 - Surface Water Drainage & Pond Capacity.1a


Shire of Ashbuton Stormwater Drainage: Pond Design

Scenario 1 = 1:100 Year 72 hour Storm

Design Period 1:100

Storm Duration (hrs): 72 hour

Total Rainfall (mm) 436.0

Catchment Area (m²): 59370 Catchment Area (m²): 132620 Catchment Area (m²): 359200 Catchment Area (m²): 190200

Runoff Coefficient, C: 0.400 Runoff Coefficient, C: 0.400 Runoff Coefficient, C: 0.400 Runoff Coefficient, C: 0.400 Design Operational Volumes

Rainfall (mm) 436.0 Rainfall (mm) 436.0 Rainfall (mm) 436.0 Rainfall (mm) 436.0 Main attenuation pond = 34,620m3

Storage Requirement (m³) 10,354 Storage Requirement (m³) 23,129 Storage Requirement (m³) 62,644 Storage Requirement (m³) 33,171 Evaporation pond #1 = 5,611m3

Total Storage Required (m3) 33,171 Evaporation pond #2 = 5,611m3

Design Volume (m3) 45,842 Total = 45,842m3

Difference (m3) 12,671

Scenario 2 = 1:100 Year 24 hour Storm

Design Period 1:100

Storm Duration (hrs): 24 hour

Rainfall (mm) 355.0

Catchment Area (m²): 59370 Catchment Area (m²): 132620 Catchment Area (m²): 359200 Catchment Area (m²): 190200

Runoff Coefficient, C: 0.400 Runoff Coefficient, C: 0.400 Runoff Coefficient, C: 0.400 Runoff Coefficient, C: 0.400

Rainfall (mm) 355.0 Rainfall (mm) 355.0 Rainfall (mm) 355.0 Rainfall (mm) 355.0

Storage Requirement (m³) 8,431 Storage Requirement (m³) 18,832 Storage Requirement (m³) 51,006 Storage Requirement (m³) 27,008

Total Storage Required (m3) 27,008

Design Volume (m3) 45,842

Difference (m3) 18,834

Rainfall Data

Volume per Catchment

Rainfall

3 - South-West Catchment 4 - Landfill Catchment1 - North Catchment 2 - North-West Catchment

Volume per Catchment

1 - North Catchment 2 - North-West Catchment 3 - South-West Catchment 4 - Landfill Catchment



Shire of Ashbuton Stormwater Drainage: Swale Design

Comments

http://onlinemanuals.txdot.gov/txdotmanuals/hyd/rational_method.htm (1)

http://www.bom.gov.au/water/designRainfalls/ifd/howtoIFDTool.shtml (2)

http://www.ce.utexas.edu/prof/maidment/CE365KSpr14/Visual/OpenChannels.pdf (3)

Design Period (yrs): 100 http://www.efm.leeds.ac.uk/CIVE/CIVE2400/OpenChannelHydraulics2.pdf (4)

Total Concentration Time, Tc (min) 45.69

1 26.7 ln(I) = A+B(ln(Tc))+C(ln(Tc))^2+D(ln(Tc))^3+E(ln(Tc))^4+F(ln(Tc))^5+G(ln(Tc))^6 (2)

2 36.3 I = intensity (mm/hr)

5 54.1 Tc = total time concentration (hr)

10 65.9 A through G = ARI coefficients (from table at top of spreadsheet)

20 80.8

50 101.7

100 118.5 2813.55411

Intensity for Tc (mm/h) 118.5

Peak Flow Rate (m3/h) 2813.55 Q = ((C*I*(A/10000))/360)*3600 for m3/hr (1) T = 10 m

C=runoff coefficient

Swale Geometry I=rainfall intensity (mm/hr)

Depth of Flow, h (m) 0.5 A=area(m2) 1 h = 0.5 m

Bottom width, b (m) 4

Side slope, S (m) 6 S = 6

Top width, T (m) 10 T = b + (2*S*h) (3) pg2

Swale Area, As (m2) 3.5 As = (b+S*h)*h (3) b = 4 m

Wetted Perimeter, Pw (m) 10.08 Pw = b + 2*h*sqrt(1+S^2) (3)

Hydraulic Radius, Rh (m) 0.347 Rh = As/Pw (3)

Hydraulic Depth, Dh (m) 0.350 Dh = As/T (3)

Flow Length (m) 150.00

Total Fall (m) 1.32

Slope of Swale, Ss 0.009 Slope = ΔRL/ΔFlow Length


Total Fall (m) 15.42



Total Fall (m) 0.88


A: Manning's coefficient, n 0.022

A: Maximum Velocity, V (m/s) 2.11 V = (1/n)*(Rh^(2/3))*(Ss^1/2) 7.37 (3)

B - Steep: Manning's coefficient, n 0.035

B - Steep: Maximum Velocity, V (m/s) 3.25 V = (1/n)*(Rh^(2/3))*(Ss^1/2) 11.39 (3)

C: Manning's coefficient, n 0.022

C: Maximum Velocity, V (m/s) 0.93 V = (1/n)*(Rh^(2/3))*(Ss^1/2) 3.26 (3)

Maximum Flow, Q (m3/s) 3.26 Q = V*As 22.02 17.62 (3)

Maximum Flow, Q (m3/h) 11751 Pass

Froude Number, Fr 1.14 Supercritical Fr = V/sqrt(g*Dh), where g = gravitational force; = 9.81 m/s2 (3)

Reynolds Number, Re (channel) 409,111 Turbulent Re = V*(As/Pw)*(1/v) = V*Rh*(1/v), where v is kinematic viscosity (m2/s); = 1.787*10^-6 @ 0°C (4) pg15

Slope C

Equations (references below)

2.1 Swale #1: Area 1 (Northern)

Rainfall Data

Slope B - Steep

Channel Flow

Slope A

h

T

h

T




Comments







Peak Flow Rate (m3/h) 7,180 Q = ((C*I*(A/10000))/360)*3600 for m3/hr (1) T = 5.36 m


I=rainfall intensity (mm/hr)




Top width, T (m) 5.36 T = b + (2*S*h) (3) pg2






Total Fall (m) 2.43



Total Fall (m) 11.60



Total Fall (m) 0.59


A: Manning's coefficient, n 0.022A: Maximum Velocity, V (m/s) 3.10 V = (1/n)*(Rh^(2/3))*(Ss^1/2) (3)

B - Steep: Manning's coefficient, n 0.035

B - Steep: Maximum Velocity, V (m/s) 2.93 V = (1/n)*(Rh^(2/3))*(Ss^1/2) (3)

C: Manning's coefficient, n 0.022

C: Maximum Velocity, V (m/s) 0.99 V = (1/n)*(Rh^(2/3))*(Ss^1/2) (3)

Maximum Flow, Q (m3/s) 2.03 Q = V*As (3)

Maximum Flow, Q (m3/h) 7,318 Pass



Slope A

Slope C

Rainfall Data

Swale Geometry

2.2 Swale #2: Area 2 (Eastern)


Slope B - Steep

Flow

h

T




Comments







Peak Flow Rate (m3/h) 11,681 Q = ((C*I*(A/10000))/360)*3600 for m3/hr (1) T = 10.6 m






Top width, T (m) 10.6 T = b + (2*S*h) (3) pg2






Total Fall (m) 1.88


Manning's coefficient, n 0.022

Maximum Velocity, V (m/s) 0.87 V = (1/n)*(Rh^(2/3))*(Ss^1/2) (3)



Froude Number, Fr 0.45 Subcritical Fr = V/sqrt(g*Dh), where g = gravitational force; = 9.81 m/s2 (3)


2.3 Swale #3: Area 3 (Southern)


Rainfall Data

Swale Geometry

Slope

Flow

h

T




Comments







Peak Flow Rate (m3/h) 8,391 Q = ((C*I*(A/10000))/360)*3600 for m3/hr (1) T = 9 m






Top width, T (m) 9 T = b + (2*S*h) (3) pg2

Swale Area, As (m2) 3 As = (b+S*h)*h (3) b = 3 m





Total Fall (m) 1.22


Manning's coefficient, n 0.009

Maximum Velocity, V (m/s) 2.17 V = (1/n)*(Rh^(2/3))*(Ss^1/2) (3)






Flow

Rainfall Data

Swale Geometry

Slope

2.4 Swale #4: Area 4 (Landfill)

h

T




: Culvert and Rock

Armouring Design Calculations


Shire of AshburtonCulvert Design Calculations

Parameter Value Units Value Units Value Units Comments

Maximum Inlet Flow Rate, Qi = 2.03 m3/s 6.51 m3/s 3.26 m3/s = Input

Maximum Outlet Flow Rate, Qo = 3.5 m3/s 6.51 m3/s 3.26 m3/s = PASS

Rainfall Event, ARI = 100 years 100 years 100 years = FAIL

Tail Water, TW = 0.5 m 0.5 m 0.5 m Height of the water designed for the swales = Factor of Safety

Box culvert width, B = 4.8 m 9.6 m 4.8 m

Box culvert Height, D = 0.9 m 0.9 m 0.9 m

Box Culvert crossectional area, A = 4.32 m2 8.64 m2 4.32 m2

Length, L = 20 m 12 m 5 m

Slope, So = 0.0117 0.0022 0.0000

Ratio Qi/B = 0.42 0.68 0.68

Allowable Head water, AHW = 0.8 m 0.8 m 0.8 m

HW/D = 0.44 m 0.6 m 0.6 m Appendix B, Figure B1, pg 146 Austroads

Hwi = 0.40 m 0.54 m 0.54 m

Check Hwi < AHW PASS PASS PASS

Factor of Safety 2.0 1.5 1.5

Entry loss coefficient, ke = 0.5 0.5 0.5

Table 3.2, pg 84 Austroads

0.5 = reinforced concrete box, square on 3 edges

Head, H = 0 m 0 m 0 m Appendix B, Figure B5, pg 150 Austroads

Critical depth, dc = 0.26 m 0.36 m 0.36 m

(dc + D)/2 = 0.58 m 0.63 m 0.63 m

ho = 0.58 m 0.63 m 0.63 m

if TW > D:

if yes, ho = TW

if if no, ho = the larger of TW and (dc + D)/2

L*So = 0.23 m 0.026 m 0 m

Headwater under outlet control conditions, Hwo = 0.35 m 0.60 m 0.63 m

Check Hwo < AHW PASS PASS PASS

Factor of Safety 2.3 1.3 1.3

Outlet Velocity 0.81 m/s 0.75 m/s 0.75 m/s Qo/A

Inlet Froude, Fri = 0.16 0.25 0.25 Qo*sqrt(B/(g(A^3)))

Outlet Froude, Fro = 0.27 0.25 0.25

*Source: Austroads Guide to Road Design - Part 5B: Drainage - Open Channels, Culverts and Floodways

**Table is a modification of the worksheet provided on page 86 of the Austroads Design Guide

Intersection Point #3Intersection Point #1

LEGEND

Intersection Point #2

TW18004 - Rock Armouring & Culvert.1a

Guide to Road Design Part 5B: Drainage – Open Channels, Culverts and Floodway

A u s t r o a d s 2 0 1 3

— 146 —

B.2 Inlet Control

Source: DTMR (2010).

Figure B 1: Headwater depth for box culvert with inlet control

Intersection Point #1 Culvert

D = 0.9m

Q/B = 0.42

HW/D = 0.44

*Assuming awingwall flare between 30 and 70 degrees

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A u s t r o a d s 2 0 1 3

— 150 —

B.3 Outlet Control


Figure B 5: Head for concrete box culverts flowing full with outlet control (n=0.012)


Q = 3.50m3/s

A = 4.32m2

ke = 0.5

L = 20m

H < 0.1m Therefore, H is considered negligible

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A u s t r o a d s 2 0 1 3

— 146 —

B.2 Inlet Control


Figure B 1: Headwater depth for box culvert with inlet control


HW/D = 0.59

D = 0.9m

Q/B = 0.68

*Assuming a wingwall flare between 30 and 70 degrees

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A u s t r o a d s 2 0 1 3

— 150 —

B.3 Outlet Control


Figure B 5: Head for concrete box culverts flowing full with outlet control (n=0.012)


H < 0.1m Therefore, H is considered negligible

Q = 3.26m3/s

A = 4.32m2

ke = 0.5

L = 5m

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A u s t r o a d s 2 0 1 3

— 43 —


Figure 2.22: Relationship between bed velocity and rock diameter

200

75

1.5 2.5

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